| 1. |
- De Keyser, J., et al.
(författare)
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In situ plasma and neutral gas observation time windows during a comet flyby : Application to the Comet Interceptor mission
- 2024
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Ingår i: Planetary and Space Science. - : Elsevier. - 0032-0633 .- 1873-5088. ; 244
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Tidskriftsartikel (refereegranskat)abstract
- A comet flyby, like the one planned for ESA's Comet Interceptor mission, places stringent requirements on spacecraft resources. To plan the time line of in situ plasma and neutral gas observations during the flyby, the size of the comet magnetosphere and neutral coma must be estimated well. For given solar irradiance and solar wind conditions, comet composition, and neutral gas expansion speed, the size of gas coma and magnetosphere during the flyby can be estimated from the gas production rate and the flyby geometry. Combined with flyby velocity, the time spent in these regions can be inferred and a data acquisition plan can be elaborated for each instrument, compatible with the limited data storage capacity. The sizes of magnetosphere and gas coma are found from a statistical analysis based on the probability distributions of gas production rate, flyby velocity, and solar wind conditions. The size of the magnetosphere as measured by bow shock standoff distance is 105-106 km near 1 au in the unlikely case of a Halley-type target comet, down to a nonexistent bow shock for targets with low activity. This translates into durations up to 103-104 seconds. These estimates can be narrowed down when a target is identified far from the Sun, and even more so as its activity can be predicted more reliably closer to the Sun. Plasma and neutral gas instruments on the Comet Interceptor main spacecraft can monitor the entire flyby by using an adaptive data acquisition strategy in the context of a record-and-playback scenario. For probes released from the main spacecraft, the inter-satellite communication link limits the data return. For a slow flyby of an active comet, the probes may not yet be released during the inbound bow shock crossing.
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| 2. |
- Maksimovic, M., et al.
(författare)
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First observations and performance of the RPW instrument on board the Solar Orbiter mission
- 2021
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 656
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Tidskriftsartikel (refereegranskat)abstract
- The Radio and Plasma Waves (RPW) instrument on the ESA Solar Orbiter mission is designed to measure in situ magnetic and electric fields and waves from the continuum up to several hundred kHz. The RPW also observes solar and heliospheric radio emissions up to 16 MHz. It was switched on and its antennae were successfully deployed two days after the launch of Solar Orbiter on February 10, 2020. Since then, the instrument has acquired enough data to make it possible to assess its performance and the electromagnetic disturbances it experiences. In this article, we assess its scientific performance and present the first RPW observations. In particular, we focus on a statistical analysis of the first observations of interplanetary dust by the instrument's Thermal Noise Receiver. We also review the electro-magnetic disturbances that RPW suffers, especially those which potential users of the instrument data should be aware of before starting their research work.
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| 3. |
- Edberg, H., et al.
(författare)
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Crimes and sentences in individuals with intellectual disability in a forensic psychiatric context: a register-based study
- 2022
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Ingår i: Epidemiology and Psychiatric Sciences. - : Cambridge University Press (CUP). - 2045-7960 .- 2045-7979. ; 31
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Tidskriftsartikel (refereegranskat)abstract
- Aims To study associations between intellectual disability (ID) and sexual and violent offending among individuals subject to pre-trial forensic psychiatric assessment. To investigate sentences following pre-trial forensic psychiatric assessment in offenders with and without ID. Methods A population-based observational study using data from pre-trial forensic psychiatric assessments in Sweden (1997-2013), the Swedish National Crime Register and several other Swedish national registers. The study population consisted of 7450 offenders (87% men, 13% women) who were subject to forensic psychiatric assessment in 1997-2013, of whom 481 (6.5%) were clinically assessed as having ID. Results ID offenders were more likely than non-ID offenders to have a sexual crime as an index crime [26.2 v. 11.5%, adjusted odds ratio (OR) 2.7, 95% confidence interval (CI) 2.02-3.58] as well as previous convictions regarding sexual offending (10.4 v. 5.6%, adj OR 2.3, 95% CI 1.70-3.12). These associations were restricted to male offenders; sexual offending was uncommon among women. Comorbid attention-deficit hyperactivity disorder reduced the association between ID and sexual offending (adj OR 2.7 v. 3.1, p = 0.017), while comorbid autism spectrum disorder had no significant influence on the association (adj OR 2.7 v. 3.0, p = 0.059). Violent crime was equally common among ID and non-ID offenders. Offenders with ID were more likely than non-ID offenders to be sentenced to forensic psychiatric care or community sanctions and measures (such as probation, conditional sentences or fines) than to prison; however, 15% of individuals who received an ID diagnosis during the forensic psychiatric assessment were sentenced to prison. Previous criminal convictions, concurrent antisocial personality disorders and substance use disorders were associated with a higher probability of a prison sentence among offenders with ID. Conclusions Sexual crime is overrepresented among offenders with ID compared to offenders with other mental disorders than ID in forensic psychiatric contexts. ID offenders become subject to forensic psychiatric care and forensic psychiatric services need evidence-based treatment programmes for offenders with ID. In addition, there is a need for early intervention strategies suitable for disability services and special education schools, in order to address the complex needs of individuals with ID and prevent sexual and violent offending.
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| 4. |
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| 5. |
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| 6. |
- Carbone, F., et al.
(författare)
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Statistical study of electron density turbulence and ion-cyclotron waves in the inner heliosphere : Solar Orbiter observations
- 2021
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 656
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Tidskriftsartikel (refereegranskat)abstract
- Context. The recently released spacecraft potential measured by the RPW instrument on board Solar Orbiter has been used to estimate the solar wind electron density in the inner heliosphere. Aims. The measurement of the solar wind's electron density, taken in June 2020, has been analysed to obtain a thorough characterization of the turbulence and intermittency properties of the fluctuations. Magnetic field data have been used to describe the presence of ion-scale waves. Methods. To study and quantify the properties of turbulence, we extracted selected intervals. We used empirical mode decomposition to obtain the generalized marginal Hilbert spectrum, equivalent to the structure functions analysis, which additionally reduced issues typical of non-stationary, short time series. The presence of waves was quantitatively determined by introducing a parameter describing the time-dependent, frequency-filtered wave power. Results. A well-defined inertial range with power-law scalng was found almost everywhere in the sample studied. However, the Kolmogorov scaling and the typical intermittency effects are only present in fraction of the samples. Other intervals have shallower spectra and more irregular intermittency, which are not described by models of turbulence. These are observed predominantly during intervals of enhanced ion frequency wave activity. Comparisons with compressible magnetic field intermittency (from the MAG instrument) and with an estimate of the solar wind velocity (using electric and magnetic field) are also provided to give general context and help determine the cause of these anomalous fluctuations.
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| 7. |
- Dimmock, A. P., et al.
(författare)
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Analysis of multiscale structures at the quasi-perpendicular Venus bow shock Results from Solar Orbiter's first Venus flyby
- 2022
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 660
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Tidskriftsartikel (refereegranskat)abstract
- Context. Solar Orbiter is a European Space Agency mission with a suite of in situ and remote sensing instruments to investigate the physical processes across the inner heliosphere. During the mission, the spacecraft is expected to perform multiple Venus gravity assist maneuvers while providing measurements of the Venusian plasma environment. The first of these occurred on 27 December 2020, in which the spacecraft measured the regions such as the distant and near Venus magnetotail, magnetosheath, and bow shock. Aims. This study aims to investigate the outbound Venus bow shock crossing measured by Solar Orbiter during the first flyby. We study the complex features of the bow shock traversal in which multiple large amplitude magnetic field and density structures were observed as well as higher frequency waves. Our aim is to understand the physical mechanisms responsible for these high amplitude structures, characterize the higher frequency waves, determine the source of the waves, and put these results into context with terrestrial bow shock observations. Methods. High cadence magnetic field, electric field, and electron density measurements were employed to characterize the properties of the large amplitude structures and identify the relevant physical process. Minimum variance analysis, theoretical shock descriptions, coherency analysis, and singular value decomposition were used to study the properties of the higher frequency waves to compare and identify the wave mode. Results. The non-planar features of the bow shock are consistent with shock rippling and/or large amplitude whistler waves. Higher frequency waves are identified as whistler-mode waves, but their properties across the shock imply they may be generated by electron beams and temperature anisotropies. Conclusions. The Venus bow shock at a moderately high Mach number (similar to 5) in the quasi-perpendicular regime exhibits complex features similar to the Earth's bow shock at comparable Mach numbers. The study highlights the need to be able to distinguish between large amplitude waves and spatial structures such as shock rippling. The simultaneous high frequency observations also demonstrate the complex nature of energy dissipation at the shock and the important question of understanding cross-scale coupling in these complex regions. These observations will be important to interpreting future planetary missions and additional gravity assist maneuvers.
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| 8. |
- Edberg, H., et al.
(författare)
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Crimes and sentences in individuals with intellectual disability in a forensic psychiatric context : a register-based study
- 2022
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Ingår i: Epidemiology and Psychiatric Sciences. - : Cambridge University Press. - 2045-7960 .- 2045-7979. ; 31
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Tidskriftsartikel (refereegranskat)abstract
- Aims: To study associations between intellectual disability (ID) and sexual and violent offending among individuals subject to pre-trial forensic psychiatric assessment. To investigate sentences following pre-trial forensic psychiatric assessment in offenders with and without ID.Methods: A population-based observational study using data from pre-trial forensic psychiatric assessments in Sweden (1997-2013), the Swedish National Crime Register and several other Swedish national registers. The study population consisted of 7450 offenders (87% men, 13% women) who were subject to forensic psychiatric assessment in 1997-2013, of whom 481 (6.5%) were clinically assessed as having ID.Results: ID offenders were more likely than non-ID offenders to have a sexual crime as an index crime [26.2 v. 11.5%, adjusted odds ratio (OR) 2.7, 95% confidence interval (CI) 2.02-3.58] as well as previous convictions regarding sexual offending (10.4 v. 5.6%, adj OR 2.3, 95% CI 1.70-3.12). These associations were restricted to male offenders; sexual offending was uncommon among women. Comorbid attention-deficit hyperactivity disorder reduced the association between ID and sexual offending (adj OR 2.7 v. 3.1, p = 0.017), while comorbid autism spectrum disorder had no significant influence on the association (adj OR 2.7 v. 3.0, p = 0.059). Violent crime was equally common among ID and non-ID offenders. Offenders with ID were more likely than non-ID offenders to be sentenced to forensic psychiatric care or community sanctions and measures (such as probation, conditional sentences or fines) than to prison; however, 15% of individuals who received an ID diagnosis during the forensic psychiatric assessment were sentenced to prison. Previous criminal convictions, concurrent antisocial personality disorders and substance use disorders were associated with a higher probability of a prison sentence among offenders with ID.Conclusions: Sexual crime is overrepresented among offenders with ID compared to offenders with other mental disorders than ID in forensic psychiatric contexts. ID offenders become subject to forensic psychiatric care and forensic psychiatric services need evidence-based treatment programmes for offenders with ID. In addition, there is a need for early intervention strategies suitable for disability services and special education schools, in order to address the complex needs of individuals with ID and prevent sexual and violent offending.
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| 9. |
- Edberg, H., et al.
(författare)
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Criminal recidivism in offenders with and without intellectual disability sentenced to forensic psychiatric care in Sweden—A 17-year follow-up study
- 2022
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Ingår i: Frontiers in Psychiatry. - : Frontiers Media SA. - 1664-0640. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Background: Offenders with intellectual disability (ID) constitute a distinct subgroup of offenders with mental disorders. Regarding criminal recidivism, it is unclear whether or not offenders with ID in forensic psychiatric settings differ from offenders without ID. Factors associated with criminal recidivism among offenders with ID have been scarcely investigated. Aim: To investigate the association between ID and criminal recidivism among offenders sentenced to forensic psychiatric care and to explore the impact of clinical, sociodemographic and offense variables. Materials and methods: We conducted a retrospective cohort study based on Swedish nationwide registers. A total of 3,365 individuals being sentenced to forensic psychiatric care in Sweden in 1997–2013 were followed from the forensic psychiatric assessment until first reconviction, death, emigration, or 31 December 2013, whichever occurred first. Cox regression models compared rates of recidivism in individuals with and without ID. Impact of clinical, sociodemographic, and offense variables on risk of criminal recidivism was presented as hazard ratios (HRs) with 95% confidence intervals (CIs). Results: Out of 3,365 offenders sentenced to forensic psychiatric care, 259 (7.7%) were diagnosed with ID. During follow-up (0–17 years, median 6 years), one third (n = 1,099) of the study population relapsed into criminality, giving a recidivism rate of 50.5 per 1,000 person-years. We observed an association between ID and a decreased risk of recidivism (HR 0.8, 95% CI 0.6–1.0, p = 0.063), although this reached statistical significance only for the subgroup of male offenders (HR 0.8, 95% CI 0.6–1.0, p = 0.040) and not females (HR 1.0, 95% CI 0.6–1.8). ID offenders with concurrent ADHD tended to have a higher rate of recidivism (73.9 per 1,000 person-years, HR 1.2, 95% CI 0.6–2.4) than ID offenders without ADHD (42.5 per 1,000 person-years, HR 0.8, 95% CI 0.6–1.1). Amongst ID offenders, concurrent autism spectrum disorder, young age or male sex were not associated with recidivism, while previous criminal convictions were strongly associated with recidivism. Conclusion: A diagnosis of ID was associated with a lower risk of criminal recidivism among male offenders sentenced to forensic psychiatric care. The association between ADHD and recidivism among ID offenders highlights eligible focus areas in the management of offenders with ID. Copyright © 2022 Edberg, Chen, Andiné, Larsson and Hirvikoski.
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| 10. |
- Edberg, Niklas J. T., et al.
(författare)
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Scale size of cometary bow shocks
- 2024
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 682
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Tidskriftsartikel (refereegranskat)abstract
- Context. In past decades, several spacecraft have visited comets to investigate their plasma environments. In the coming years, Comet Interceptor will make yet another attempt. This time, the target comet and its outgassing activity are unknown and may not be known before the spacecraft has been launched into its parking orbit, where it will await a possible interception. If the approximate outgassing rate can be estimated remotely when a target has been identified, it is desirable to also be able to estimate the scale size of the plasma environment, defined here as the region bound by the bow shock.Aims. This study aims to combine previous measurements and simulations of cometary bow shock locations to gain a better understanding of how the scale size of cometary plasma environments varies. We compare these data with models of the bow shock size, and we furthermore provide an outgassing rate-dependent shape model of the bow shock. We then use this to predict a range of times and cometocentric distances for the crossing of the bow shock by Comet Interceptor, together with expected plasma density measurements along the spacecraft track.Methods. We used data of the location of cometary bow shocks from previous spacecraft missions, together with simulation results from previously published studies. We compared these results with an existing model of the bow shock stand-off distance and expand on this to provide a shape model of cometary bow shocks. The model in particular includes the cometary outgassing rate, but also upstream solar wind conditions, ionisation rates, and the neutral flow velocity.Results. The agreement between the gas-dynamic model and the data and simulation results is good in terms of the stand-off distance of the bow shock as a function of the outgassing rate. For outgassing rates in the range of 1027–1031–s-1, the scale size of cometary bow shocks can vary by four orders of magnitude, from about 102 km to 106 km, for an ionisation rate, flow velocity, and upstream solar wind conditions typical of those at 1 AU. The proposed bow shock shape model shows that a comet plasma environment can range in scale size from the plasma environment of Mars to about half of that of Saturn.Conclusions. The model-data agreement allows for the planning of upcoming spacecraft comet encounters, such as that of Comet Interceptor, when a target has been identified and its outgassing rate is determined. We conclude that the time a spacecraft can spend within the plasma environment during a flyby can range from minutes to days, depending on the comet that is visited and on the flyby speed. However, to capture most of the comet plasma environment, including pick-up ions and upstream plasma waves, and to ensure the highest possible scientific return, measurements should still start well upstream of the expected bow shock location. From the plasma perspective, the selected target should preferably be an active comet with the lowest possible flyby velocity.
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| 11. |
- Edberg, Richard, et al.
(författare)
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Effects of uniaxial pressure on the spin ice Ho2Ti2O7
- 2020
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Ingår i: Physical Review B. - : American Physical Society. - 2469-9950 .- 2469-9969. ; 102:18
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Tidskriftsartikel (refereegranskat)abstract
- The spin ice materials Ho2Ti2O7 and Dy2Ti2O7 are experimental and theoretical exemplars of highly frustrated magnetic materials. However, the effects of applied uniaxial pressure are not well studied, and here we report magnetization measurements of Ho2Ti2O7 under uniaxial pressure applied in the [001], [111], and [110] crystalline directions. The basic features are captured by an extension of the dipolar spin ice model. We find a good match between our model and measurements with pressures applied along two of the three directions, and we extend the framework to discuss the influence of crystal misalignment for the third direction. The parameters determined from the magnetization measurements reproduce neutron scattering measurements that we perform under uniaxial pressure applied along the [110] crystalline direction. In the detailed analysis, we include the recently verified susceptibility dependence of the demagnetizing factor. Our work demonstrates the application of a moderate applied pressure to modify the magnetic interaction parameters. The knowledge can be used to predict critical pressures needed to induce new phases and transitions in frustrated materials, and in the case of Ho2Ti2O7 we expect a transition to a ferromagnetic ground state for uniaxial pressures above 3.3 GPa.
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| 12. |
- Graham, Daniel B., et al.
(författare)
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Kinetic electrostatic waves and their association with current structures in the solar wind
- 2021
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 656
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Tidskriftsartikel (refereegranskat)abstract
- Context. A variety of kinetic electrostatic and electromagnetic waves develop in the solar wind and the relationship between these waves and larger scale structures, such as current sheets and ongoing turbulence, remain a topic of investigation. Similarly, the instabilities producing ion-acoustic waves in the solar wind are still an open question. Aims. The goals of this paper are to investigate electrostatic Langmuir and ion-acoustic waves in the solar wind at 0.5 AU and determine whether current sheets and associated streaming instabilities can produce the observed waves. The relationship between these waves and currents observed in the solar wind is investigated statistically. Methods. Solar Orbiter's Radio and Plasma Waves instrument suite provides high-resolution snapshots of the fluctuating electric field. The Low Frequency Receiver resolves the waveforms of ion-acoustic waves and the Time Domain Sampler resolves the waveforms of both ion-acoustic and Langmuir waves. Using these waveform data, we determine when these waves are observed in relation to current structures in the solar wind, estimated from the background magnetic field. Results. Langmuir and ion-acoustic waves are frequently observed in the solar wind. Ion-acoustic waves are observed about 1% of the time at 0.5 AU. The waves are more likely to be observed in regions of enhanced currents. However, the waves typically do not occur at current structures themselves. The observed currents in the solar wind are too small to drive instability by the relative drift between single ion and electron populations. When multi-component ion or electron distributions are present, the observed currents may be sufficient for instabilities to occur. Ion beams are the most plausible source of ion-acoustic waves in the solar wind. The spacecraft potential is confirmed to be a reliable probe of the background electron density when comparing the peak frequencies of Langmuir waves with the plasma frequency calculated from the spacecraft potential.
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| 13. |
- Hadid, L. Z., et al.
(författare)
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Solar Orbiter's first Venus flyby : Observations from the Radio and Plasma Wave instrument
- 2021
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 656
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Tidskriftsartikel (refereegranskat)abstract
- Context. On December 27, 2020, Solar Orbiter completed its first gravity assist manoeuvre of Venus (VGAM1). While this flyby was performed to provide the spacecraft with sufficient velocity to get closer to the Sun and observe its poles from progressively higher inclinations, the Radio and Plasma Wave (RPW) consortium, along with other operational in situ instruments, had the opportunity to perform high cadence measurements and study the plasma properties in the induced magnetosphere of Venus.Aims. In this paper, we review the main observations of the RPW instrument during VGAM1. They include the identification of a number of magnetospheric plasma wave modes, measurements of the electron number densities computed using the quasi-thermal noise spectroscopy technique and inferred from the probe-to-spacecraft potential, the observation of dust impact signatures, kinetic solitary structures, and localized structures at the bow shock, in addition to the validation of the wave normal analysis on-board from the Low Frequency Receiver.Methods. We used the data products provided by the different subsystems of RPW to study Venus' induced magnetosphere.Results. The results include the observations of various electromagnetic and electrostatic wave modes in the induced magnetosphere of Venus: strong emissions of similar to 100 Hz whistler waves are observed in addition to electrostatic ion acoustic waves, solitary structures and Langmuir waves in the magnetosheath of Venus. Moreover, based on the different levels of the wave amplitudes and the large-scale variations of the electron number densities, we could identify different regions and boundary layers at Venus.Conclusions. The RPW instrument provided unprecedented AC magnetic and electric field measurements in Venus' induced magnetosphere for continuous frequency ranges and with high time resolution. These data allow for the conclusive identification of various plasma waves at higher frequencies than previously observed and a detailed investigation regarding the structure of the induced magnetosphere of Venus. Furthermore, noting that prior studies were mainly focused on the magnetosheath region and could only reach 10-12 Venus radii (R-V) down the tail, the particular orbit geometry of Solar Orbiter's VGAM1, allowed the first investigation of the nature of the plasma waves continuously from the bow shock to the magnetosheath, extending to similar to 70R(V) in the far distant tail region.
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| 14. |
- Johansson, Fredrik, et al.
(författare)
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Implications from secondary emission from neutral impact on Cassini plasma and dust measurements
- 2022
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Ingår i: Monthly notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 515:2, s. 2340-2350
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Tidskriftsartikel (refereegranskat)abstract
- We investigate the role of secondary electron and ion emission from impact of gas molecules on the Cassini Langmuir probe (RPWS-LP or LP) measurements in the ionosphere of Saturn. We add a model of the emission currents, based on laboratory measurements and data from comet 1P/Halley, to the equations used to derive plasma parameters from LP bias voltage sweeps. Reanalysing several hundred sweeps from the Cassini Grand Finale orbits, we find reasonable explanations for three open conundrums from previous LP studies of the Saturn ionosphere. We find an explanation for the observed positive charging of the Cassini spacecraft, the possibly overestimated ionospheric electron temperatures, and the excess ion current reported. For the sweeps analysed in detail, we do not find (indirect or direct) evidence of dust having a significant charge-carrying role in Saturn's ionosphere. We also produce an estimate of H2O number density from the last six revolutions of Cassini through Saturn's ionosphere in greater detail than reported by the Ion and Neutral Mass Spectrometer. Our analysis reveals an ionosphere that is highly structured in latitude across all six final revolutions, with mixing ratios varying with two orders of magnitude in latitude and one order of magnitude between revolutions and altitude. The result is generally consistent with an empirical photochemistry model balancing the production of H+ ions with the H+ loss through charge transfer with e.g. H2O, CH4, and CO2, for which water vapour appears as the likeliest dominant source of the signal in terms of yield and concentration.
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| 15. |
- Johansson, Fredrik, et al.
(författare)
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Plasma densities, flow, and solar EUV flux at comet 67P : A cross-calibration approach
- 2021
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 653
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Tidskriftsartikel (refereegranskat)abstract
- Context. During its two-year mission at comet 67P, Rosetta nearly continuously monitored the inner coma plasma environment for gas production rates varying over three orders of magnitude, at distances to the nucleus ranging from a few to a few hundred kilometres. To achieve the best possible measurements, cross-calibration of the plasma instruments is needed. Aims. Our goal is to provide a consistent plasma density dataset for the full mission, while in the process providing a statistical characterisation of the plasma in the inner coma and its evolution.Methods. We constructed physical models for two different methods to cross-calibrate the spacecraft potential and the ion current as measured by the Rosetta Langmuir probes (LAP) to the electron density as measured by the Mutual Impedance Probe (MIP). We also described the methods used to estimate spacecraft potential, and validated the results with the Ion Composition Analyser (ICA).Results. We retrieve a continuous plasma density dataset for the entire cometary mission with a much improved dynamical range compared to any plasma instrument alone and, at times, improve the temporal resolution from 0.24-0.74 Hz to 57.8 Hz. The physical model also yields, at a three-hour time resolution, ion flow speeds and a proxy for the solar EUV flux from the photoemission from the Langmuir probes.Conclusions. We report on two independent mission-wide estimates of the ion flow speed that are consistent with the bulk H2O+ ion velocities as measured by the ICA. We find the ion flow to consistently be much faster than the neutral gas over the entire mission, lending further evidence that the ions are collisionally decoupled from the neutrals in the coma. Measurements of ion speeds from Rosetta are therefore not consistent with the assumptions made in previously published plasma density models of the comet 67P's ionosphere at the start and end of the mission. Also, the measured EUV flux is perfectly consistent with independently derived values previously published from LAP and lends support for the conclusions drawn regarding an attenuation of solar EUV from a distant nanograin dust population, when the comet activity was high. The new density dataset is consistent with the existing MIP density dataset, but it facilitates plasma analysis on much shorter timescales, and it also covers long time periods where densities were too low to be measured by MIP.
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| 16. |
- Jones, Geraint H., et al.
(författare)
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The Comet Interceptor Mission
- 2024
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Ingår i: Space Science Reviews. - : Springer Nature. - 0038-6308 .- 1572-9672. ; 220:1
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Tidskriftsartikel (refereegranskat)abstract
- Here we describe the novel, multi-point Comet Interceptor mission. It is dedicated to the exploration of a little-processed long-period comet, possibly entering the inner Solar System for the first time, or to encounter an interstellar object originating at another star. The objectives of the mission are to address the following questions: What are the surface composition, shape, morphology, and structure of the target object? What is the composition of the gas and dust in the coma, its connection to the nucleus, and the nature of its interaction with the solar wind? The mission was proposed to the European Space Agency in 2018, and formally adopted by the agency in June 2022, for launch in 2029 together with the Ariel mission. Comet Interceptor will take advantage of the opportunity presented by ESA’s F-Class call for fast, flexible, low-cost missions to which it was proposed. The call required a launch to a halo orbit around the Sun-Earth L2 point. The mission can take advantage of this placement to wait for the discovery of a suitable comet reachable with its minimum Δ V capability of 600 ms − 1 . Comet Interceptor will be unique in encountering and studying, at a nominal closest approach distance of 1000 km, a comet that represents a near-pristine sample of material from the formation of the Solar System. It will also add a capability that no previous cometary mission has had, which is to deploy two sub-probes – B1, provided by the Japanese space agency, JAXA, and B2 – that will follow different trajectories through the coma. While the main probe passes at a nominal 1000 km distance, probes B1 and B2 will follow different chords through the coma at distances of 850 km and 400 km, respectively. The result will be unique, simultaneous, spatially resolved information of the 3-dimensional properties of the target comet and its interaction with the space environment. We present the mission’s science background leading to these objectives, as well as an overview of the scientific instruments, mission design, and schedule.
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| 17. |
- Khotyaintsev, Yu, V, et al.
(författare)
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Density fluctuations associated with turbulence and waves First observations by Solar Orbiter
- 2021
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 656
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Tidskriftsartikel (refereegranskat)abstract
- Aims. The aim of this work is to demonstrate that the probe-to-spacecraft potential measured by RPW on Solar Orbiter can be used to derive the plasma (electron) density measurement, which exhibits both a high temporal resolution and a high level of accuracy. To investigate the physical nature of the solar wind turbulence and waves, we analyze the density and magnetic field fluctuations around the proton cyclotron frequency observed by Solar Orbiter during the first perihelion encounter (similar to 0.5AU away from the Sun). Methods. We used the plasma density based on measurements of the probe-to-spacecraft potential in combination with magnetic field measurements by MAG to study the fields and density fluctuations in the solar wind. In particular, we used the polarization of the wave magnetic field, the phase between the compressible magnetic field and density fluctuations, and the compressibility ratio (the ratio of the normalized density fluctuations to the normalized compressible fluctuations of B) to characterize the observed waves and turbulence. Results. We find that the density fluctuations are 180 degrees out of phase (anticorrelated) with the compressible component of magnetic fluctuations for intervals of turbulence, whereas they are in phase for the circular-polarized waves. We analyze, in detail, two specific events with a simultaneous presence of left- and right-handed waves at di fferent frequencies. We compare the observed wave properties to a prediction of the three-fluid (electrons, protons, and alphas) model. We find a limit on the observed wavenumbers, 10(-6) < k < 7 > 10(-6) m(-1), which corresponds to a wavelength of 7 x 10(6) > lambda > 10(6) m. We conclude that it is most likely that both the leftand right-handed waves correspond to the low-wavenumber part (close to the cut-o ff at Omega(cHe++)) of the proton-band electromagnetic ion cyclotron (left-handed wave in the plasma frame confined to the frequency range Omega(cHe++) < omega < Omega(cp)) waves propagating in the outwards and inwards directions, respectively. The fact that both wave polarizations are observed at the same time and the identified wave mode has a low group velocity suggests that the double-banded events occur in the source regions of the waves.
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| 18. |
- Sjöberg, Marina, et al.
(författare)
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Documentation of older people's end-of-life care in the context of specialised palliative care : a retrospective review of patient records.
- 2021
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Ingår i: BMC Palliative Care. - 1472-684X .- 1472-684X. ; 20:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Palliative care focuses on identifying, from a holistic perspective, the needs of those experiencing problems associated with life-threatening illnesses. As older people approach the end of their lives, they can experience a complex series of problems that health-care professionals must identify and document in their patients' records. Documentation is thus important for ensuring high-quality patient care. Previous studies of documentation in older people's patient records performed in various care contexts have shown that such documentation almost exclusively concerns physical problems. This study explores, in the context of Swedish specialised palliative care, the content of documentation in older people's patient records, focusing on documented problems, wishes, aspects of wellbeing, use of assessment tools, interventions, and documentation associated with the person's death.METHODS: A retrospective review based on randomly selected records (n = 92) of older people receiving specialised palliative care, at home or in a palliative in-patient ward, who died in 2017. A review template was developed based on the literature and on a review of sampled records of patients who died the preceding year. The template was checked for inter-rater agreement and used to code all clinical notes in the patients' records. Data were processed using descriptive statistics.RESULTS: The most common clinical notes in older people's patient records concerned interventions (n = 16,031, 71%), mostly related to pharmacological interventions (n = 4318, 27%). The second most common clinical notes concerned problems (n = 2804, 12%), pain being the most frequent, followed by circulatory, nutrition, and anxiety problems. Clinical notes concerning people's wishes and wellbeing-related details were documented, but not frequently. Symptom assessment tools, except for pain assessments, were rarely used. More people who received care in palliative in-patient wards died alone than did people who received care in their own homes.CONCLUSIONS: Identifying and documenting the complexity of problems in a more structured and planned way could be a method for implementing a more holistic approach to end-of-life care. Using patient-reported outcome measures capturing more than one symptom or problem, and a systematic documentation structure would help in identifying unmet needs and developing holistic documentation of end-of-life care.
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| 19. |
- Sjöberg, Marina, et al.
(författare)
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Documentation of older people's end-of-life care in the context of specialised palliative care : a retrospective review of patient records.
- 2021
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Ingår i: BMC Palliative Care. - : BioMed Central Ltd.. - 1472-684X. ; 20:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Palliative care focuses on identifying, from a holistic perspective, the needs of those experiencing problems associated with life-threatening illnesses. As older people approach the end of their lives, they can experience a complex series of problems that health-care professionals must identify and document in their patients' records. Documentation is thus important for ensuring high-quality patient care. Previous studies of documentation in older people's patient records performed in various care contexts have shown that such documentation almost exclusively concerns physical problems. This study explores, in the context of Swedish specialised palliative care, the content of documentation in older people's patient records, focusing on documented problems, wishes, aspects of wellbeing, use of assessment tools, interventions, and documentation associated with the person's death. METHODS: A retrospective review based on randomly selected records (n = 92) of older people receiving specialised palliative care, at home or in a palliative in-patient ward, who died in 2017. A review template was developed based on the literature and on a review of sampled records of patients who died the preceding year. The template was checked for inter-rater agreement and used to code all clinical notes in the patients' records. Data were processed using descriptive statistics. RESULTS: The most common clinical notes in older people's patient records concerned interventions (n = 16,031, 71%), mostly related to pharmacological interventions (n = 4318, 27%). The second most common clinical notes concerned problems (n = 2804, 12%), pain being the most frequent, followed by circulatory, nutrition, and anxiety problems. Clinical notes concerning people's wishes and wellbeing-related details were documented, but not frequently. Symptom assessment tools, except for pain assessments, were rarely used. More people who received care in palliative in-patient wards died alone than did people who received care in their own homes. CONCLUSIONS: Identifying and documenting the complexity of problems in a more structured and planned way could be a method for implementing a more holistic approach to end-of-life care. Using patient-reported outcome measures capturing more than one symptom or problem, and a systematic documentation structure would help in identifying unmet needs and developing holistic documentation of end-of-life care.
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| 20. |
- Sjöberg, Marina, et al.
(författare)
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Existential aspects documented in older people’s patient records in the context of specialized palliative care : a retrospective review
- 2022
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Ingår i: BMC Health Services Research. - : BioMed Central Ltd.. - 1472-6963. ; 22:1, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- Background: Documentation of older people’s end-of-life care should cover the care given and provide an overview of their entire situation. Older people approaching the end of life often have complex symptoms, live with bodily losses, and face an unknown future in which existential aspects come to the forefront. Knowledge of the existential aspects recorded in palliative care documentation is sparse and merits improvement. This knowledge is relevant to the development of more holistic documentation and is necessary in order to promote reflection on and discussion of documentation of the sensitive existential considerations arising in palliative care. The aim of this study was to describe the documentation of existential aspects in the patient records of older people receiving specialized palliative care. Methods: Data were obtained from a retrospective review of the free-text notes in 84 records of randomly selected patients aged ≥75 years enrolled in specialized palliative care units who died in 2017. The notes were analysed using an inductive qualitative content analysis. Results: The notes documented existential aspects in terms of connotations of well-being and ill-being. Documented existential aspects were related to the patients’ autonomy concerning loss of freedom and self-determination, social connectedness concerning loneliness and communion, emotional state concerning anxiety and inner peace, and state of being concerning despair and hope. The notes on existential aspects were, however, not recorded in a structured way and no care plans related to existential aspects were found. Conclusions: Existential aspects concerning both ill-being and well-being were sparsely and unsystematically documented in older people’s patient records, but when notes were extracted from these records and analysed, patterns became evident. Existential aspects form an important basis for delivering person-centred palliative care. There is a need to develop structured documentation concerning existential aspects; otherwise, patients’ thoughts and concerns may remain unknown to healthcare professionals.
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| 21. |
- Steinvall, Konrad, et al.
(författare)
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Solar wind current sheets and deHoffmann-Teller analysis First results from Solar Orbiter's DC electric field measurements
- 2021
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 656
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Tidskriftsartikel (refereegranskat)abstract
- Context. Solar Orbiter was launched on 10 February 2020 with the purpose of investigating solar and heliospheric physics using a payload of instruments designed for both remote and in situ studies. Similar to the recently launched Parker Solar Probe, and unlike earlier missions, Solar Orbiter carries instruments designed to measure low-frequency DC electric fields. Aims. In this paper, we assess the quality of the low-frequency DC electric field measured by the Radio and Plasma Waves instrument (RPW) on Solar Orbiter. In particular, we investigate the possibility of using Solar Orbiter's DC electric and magnetic field data to estimate the solar wind speed. Methods. We used a deHoffmann-Teller (HT) analysis, based on measurements of the electric and magnetic fields, to find the velocity of solar wind current sheets, which minimises a single component of the electric field. By comparing the HT velocity to the proton velocity measured by the Proton and Alpha particle Sensor (PAS), we have developed a simple model for the effective antenna length, L-eff of the E-field probes. We then used the HT method to estimate the speed of the solar wind. Results. Using the HT method, we find that the observed variations in E-y are often in excellent agreement with the variations in the magnetic field. The magnitude of E-y, however, is uncertain due to the fact that the L-eff depends on the plasma environment. Here, we derive an empirical model relating L-eff to the Debye length, which we can use to improve the estimate of E-y and, consequently, the estimated solar wind speed. Conclusions. The low-frequency electric field provided by RPW is of high quality. Using the deHoffmann-Teller analysis, Solar Orbiter's magnetic and electric field measurements can be used to estimate the solar wind speed when plasma data are unavailable.
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| 22. |
- Volwerk, M., et al.
(författare)
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Solar Orbiter's first Venus flyby MAG observations of structures and waves associated with the induced Venusian magnetosphere
- 2021
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 656
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Tidskriftsartikel (refereegranskat)abstract
- Context. The induced magnetosphere of Venus is caused by the interaction of the solar wind and embedded interplanetary magnetic field with the exosphere and ionosphere of Venus. Solar Orbiter entered Venus's magnetotail far downstream, > 70 Venus radii, of the planet and exited the magnetosphere over the north pole. This offered a unique view of the system over distances that had only been flown through before by three other missions, Mariner 10, Galileo, and BepiColombo.Aims. In this study, we study the large-scale structure and activity of the induced magnetosphere as well as the high-frequency plasma waves both in the magnetosphere and in a limited region upstream of the planet where interaction with Venus's exosphere is expected.Methods. The large-scale structure of the magnetosphere was studied with low-pass filtered data and identified events are investigated with a minimum variance analysis as well as combined with plasma data. The high-frequency plasma waves were studied with spectral analysis.Results. We find that Venus's magnetotail is very active during the Solar Orbiter flyby. Structures such as flux ropes and reconnection sites were encountered, in addition to a strong overdraping of the magnetic field downstream of the bow shock and planet. High-frequency plasma waves (up to six times the local proton cyclotron frequency) are observed in the magnetotail, which are identified as Doppler-shifted proton cyclotron waves, whereas in the upstream solar wind, these waves appear just below the proton cyclotron frequency (as expected) but are very patchy. The bow shock is quasi-perpendicular, however, expected mirror mode activity is not found directly behind it; instead, there is strong cyclotron wave power. This is most likely caused by the relatively low plasma-beta behind the bow shock. Much further downstream, magnetic hole or mirror mode structures are identified in the magnetosheath.
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