| 1. |
- Aartsen, M. G., et al.
(författare)
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Astrophysical neutrinos and cosmic rays observed by IceCube
- 2018
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Ingår i: Advances in Space Research. - : Elsevier BV. - 0273-1177 .- 1879-1948. ; 62:10, s. 2902-2930
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Tidskriftsartikel (refereegranskat)abstract
- The core mission of the IceCube neutrino observatory is to study the origin and propagation of cosmic rays. IceCube, with its surface component IceTop, observes multiple signatures to accomplish this mission. Most important are the astrophysical neutrinos that are produced in interactions of cosmic rays, close to their sources and in interstellar space. IceCube is the first instrument that measures the properties of this astrophysical neutrino flux and constrains its origin. In addition, the spectrum, composition, and anisotropy of the local cosmic-ray flux are obtained from measurements of atmospheric muons and showers. Here we provide an overview of recent findings from the analysis of IceCube data, and their implications to our understanding of cosmic rays.
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| 2. |
- Amati, L., et al.
(författare)
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The THESEUS space mission concept : science case, design and expected performances
- 2018
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Ingår i: Advances in Space Research. - : ELSEVIER SCI LTD. - 0273-1177 .- 1879-1948. ; 62:1, s. 191-244
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Tidskriftsartikel (refereegranskat)abstract
- THESEUS is a space mission concept aimed at exploiting Gamma-Ray Bursts for investigating the early Universe and at providing a substantial advancement of multi-messenger and time-domain astrophysics. These goals will be achieved through a unique combination of instruments allowing GRB and X-ray transient detection over a broad field of view (more than 1 sr) with 0.5-1 arcmin localization, an energy band extending from several MeV down to 0.3 keV and high sensitivity to transient sources in the soft X-ray domain, as well as on-board prompt (few minutes) follow-up with a 0.7 m class IR telescope with both imaging and spectroscopic capabilities. THESEUS will be perfectly suited for addressing the main open issues in cosmology such as, e.g., star formation rate and metallicity evolution of the inter-stellar and intra-galactic medium up to redshift similar to 10, signatures of Pop III stars, sources and physics of re-ionization, and the faint end of the galaxy luminosity function. In addition, it will provide unprecedented capability to monitor the X-ray variable sky, thus detecting, localizing, and identifying the electromagnetic counterparts to sources of gravitational radiation, which may be routinely detected in the late '20s/early '30s by next generation facilities like aLIGO/ aVirgo, eLISA, KAGRA, and Einstein Telescope. THESEUS will also provide powerful synergies with the next generation of multi-wavelength observatories (e.g., LSST, ELT, SKA, CTA, ATHENA).
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| 3. |
- Anker, A., et al.
(författare)
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Targeting ultra-high energy neutrinos with the ARIANNA experiment
- 2019
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Ingår i: Advances in Space Research. - : Elsevier BV. - 0273-1177 .- 1879-1948. ; 64:12, s. 2595-2609
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Tidskriftsartikel (refereegranskat)abstract
- The measurement of ultra-high energy (UHE) neutrinos (E > 10(16) eV) opens a new field of astronomy with the potential to reveal the sources of ultra-high energy cosmic rays especially if combined with observations in the electromagnetic spectrum and gravitational waves. The ARIANNA pilot detector explores the detection of UHE neutrinos with a surface array of independent radio detector stations in Antarctica which allows for a cost-effective instrumentation of large volumes. Twelve stations are currently operating successfully at the Moore's Bay site (Ross Ice Shelf) in Antarctica and at the South Pole. We will review the current state of ARIANNA and its main results. We report on a newly developed wind generator that successfully operates in the harsh Antarctic conditions and powers the station for a substantial time during the dark winter months. The robust ARIANNA surface architecture, combined with environmentally friendly solar and wind power generators, can be installed at any deep ice location on the planet and operated autonomously. We report on the detector capabilities to determine the neutrino direction by reconstructing the signal arrival direction of a 800 m deep calibration pulser, and the reconstruction of the signal polarization using the more abundant cosmic-ray air showers. Finally, we describe a large-scale design - ARIA - that capitalizes on the successful experience of the ARIANNA operation and is designed sensitive enough to discover the first UHF neutrino.
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| 4. |
- Ashraf, Shakeel, 1984-, et al.
(författare)
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Determination of complex refractive index of SU-8 by Kramers-Kronig dispersion relation method at the wavelength range 2.5 – 22.0 μm
- 2019
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Ingår i: Journal of Quantitative Spectroscopy and Radiative Transfer. - : Elsevier BV. - 0022-4073 .- 1879-1352. ; 224, s. 309-311
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Tidskriftsartikel (refereegranskat)abstract
- Accurate determination of the complex refractive index of SU-8 epoxy has significant for the wide variety of applications in optical sensor technology at IR range. The complex refractive index of SU-8 is determined by recording the transmission of light spectra for the wavelength range of 2.5 – 22.0 μm. The data analysis is based on the Kramers-Kronig dispersion relation method. The method has several merits, such as ease of operation, non-contact technique, measurement accuracy, and rapid measurement. The present method is not restricted to the case of SU-8 but it is also proposed to be applicable across a broad range of applications, such as assessment of the optical properties of paints and biomedical samples.
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| 5. |
- Bazzocchi, Michael C. F., et al.
(författare)
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Formation of Multiple Landers for Asteroid Detumbling
- 2018
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Ingår i: Advances in Space Research. - : Elsevier. - 0273-1177 .- 1879-1948. ; 62:3, s. 732-744
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Tidskriftsartikel (refereegranskat)abstract
- This work develops a method for ascertaining the landing locations and thruster orientations of a formation of multiple spacecraft on an irregular asteroid for discrete time optimal detumbling control, as a prerequisite to asteroid redirection. Asteroid geometries are known to be extremely irregular, especially for small asteroids, which are the typical targets for redirection missions. The method entails the modelling of asteroids as convex polyhedra with triangular facets, and computing the mass and inertial properties through the divergence theorem and Green’s theorem. Given the asteroid geometry, mass, and inertial properties, the feasible lander locations and thruster orientations are determined. The model ensures full attitude control of the asteroid, using multiple spacecraft with fixed-orientation, low-thrust modules, through measures imposed on the location and orientation of each thruster. A linear control scheme is employed to assess the time and fuel requirements of the asteroid detumbling maneuver, given feasible spacecraft formation configurations and thruster orientations. The method then assesses the detumbling time performance of each formation configuration to determine the discrete optimal landed formation configuration for a given asteroid. Simulations are performed to demonstrate the method using an irregular asteroid with characteristics derived from available asteroid data. Extensions of the method are further discussed in light of the results.
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| 6. |
- Belov, A., et al.
(författare)
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The integration and testing of the Mini-EUSO multi-level trigger system
- 2017
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Ingår i: Advances in Space Research. - : Elsevier. - 0273-1177.
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Tidskriftsartikel (refereegranskat)abstract
- The Mini-EUSO telescope is designed by the JEM-EUSO Collaboration to observe the UV emission of the Earth from the vantage point of the International Space Station (ISS) in low Earth orbit. The main goal of the mission is to map the Earth in the UV, thus increasing the technological readiness level of future EUSO experiments and to lay the groundwork for the detection of Extreme Energy Cosmic Rays (EECRs) from space (Ebisuzaki et al., 2014). Due to its high time resolution of 2.5 μs, Mini-EUSO is capable of detecting a wide range of UV phenomena in the Earth’s atmosphere. In order to maximise the scientific return of the mission, it is necessary to implement a multi-level trigger logic for data selection over different timescales. This logic is key to the success of the mission and thus must be thoroughly tested and carefully integrated into the data processing system prior to the launch. This article introduces the motivation behind the trigger design and details the integration and testing of the logic.
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| 7. |
- Bruno, A., et al.
(författare)
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Geomagnetically trapped, albedo and solar energetic particles : Trajectory analysis and flux reconstruction with PAMELA
- 2017
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Ingår i: Advances in Space Research. - : Elsevier. - 0273-1177 .- 1879-1948. ; 60:4, s. 788-795
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Tidskriftsartikel (refereegranskat)abstract
- The PAMELA satellite experiment is providing comprehensive observations of the interplanetary and magnetospheric radiation in the near-Earth environment. Thanks to its identification capabilities and the semi-polar orbit, PAMELA is able to precisely measure the energetic spectra and the angular distributions of the different cosmic-ray populations over a wide latitude region, including geomagnetically trapped and albedo particles. Its observations comprise the solar energetic particle events between solar cycles 23 and 24, and the geomagnetic cutoff variations during magnetospheric storms. PAMELA's measurements are supported by an accurate analysis of particle trajectories in the Earth's magnetosphere based on a realistic geomagnetic field modeling, which allows the classification of particle populations of different origin and the investigation of the asymptotic directions of arrival.
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| 8. |
- Capel, Francesca, et al.
(författare)
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Mini-EUSO : A high resolution detector for the study of terrestrial and cosmic UV emission from the International Space Station
- 2017
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Ingår i: Advances in Space Research. - : Elsevier. - 0273-1177 .- 1879-1948.
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Tidskriftsartikel (refereegranskat)abstract
- The Mini-EUSO instrument is a UV telescope to be placed inside the International Space Station (ISS), looking down on the Earth from a nadir-facing window in the Russian Zvezda module. Mini-EUSO will map the earth in the UV range (300-400. nm) with a spatial resolution of 6.11. km and a temporal resolution of 2.5. μs, offering the opportunity to study a variety of atmospheric events such as transient luminous events (TLEs) and meteors, as well as searching for strange quark matter and bioluminescence. Furthermore, Mini-EUSO will be used to detect space debris to verify the possibility of using a EUSO-class telescope in combination with a high energy laser for space debris remediation. The high-resolution mapping of the UV emissions from Earth orbit allows Mini-EUSO to serve as a pathfinder for the study of Extreme Energy Cosmic Rays (EECRs) from space by the JEM-EUSO collaboration.
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| 9. |
- Chen, Zhan-Bin, et al.
(författare)
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Theoretical energies, transition rates, lifetimes, hyperfine interaction constants and Lande g(J-)factors for the Se XXVII spectrum of fusion interest
- 2018
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Ingår i: Journal of Quantitative Spectroscopy and Radiative Transfer. - : Elsevier. - 0022-4073 .- 1879-1352. ; 206, s. 213-232
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Tidskriftsartikel (refereegranskat)abstract
- An extensive set of level energies, wavelengths, line strengths, oscillator strengths, lifetimes, hyperfine structures, Lande g(J)-factors, electric dipole (E1), magnetic dipole (M1), electric quadrupole (E2), and magnetic quadrupole (M2) radiative transition rates among the lowest 318 states arising from the 2s(2)2p(4), 2s2(p)5, 2p(6), 2s(2)2p(3)3l (l = 0, 1, 2), 2s2p(4)31 (l = 0, 1, 2), 2p(5)3l (l = 0, 1, 2), and 2s(2)2p(3)4l (l = 0, 1, 2, 3) configurations has been obtained for Se XXVII. These new data, calculated within the frameworks of the multi-configuration Dirac-Hartree-Fock method and the second-order many-body perturbation theory, fill in the gap existing in the atomic data needed for the diagnostic processes of tokamak plasmas. Using two methods allowed us to make an intercomparison and to estimate the uncertainties on the obtained data. The results arising in the two sets of calculations are quite close, suggesting that there is a high degree of convergence achieved in our work. i.e., our two sets of energies agree to better than 0.02%, and the lifetimes mostly agree to within 2%. Comparison is also made with the limited number of experimental data and previous computations to assess the accuracy of our calculations. (C) 2017 Elsevier Ltd. All rights reserved.
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| 10. |
- Dikpati, Mausumi, et al.
(författare)
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Role of response time of a Babcock-Leighton solar dynamo model in meridional flow-speed reconstruction by EnKF data assimilation
- 2016
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Ingår i: Advances in Space Research. - : Elsevier BV. - 0273-1177 .- 1879-1948. ; 58:8, s. 1589-1595
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Tidskriftsartikel (refereegranskat)abstract
- Ensemble Kalman Filter in the framework of Data Assimilation Research Testbed (DART) has been successfully implemented into a 2D kinematic flux-transport dynamo model by Dikpati and colleagues in order to do a parameter estimation, the parameter being the meridional flow-speed as function of time. They performed several 'Observing System Simulation Experiments' (OSSEs), and showed that an optimal reconstruction of time-series of meridional flow-speed can be obtained by using 16 ensemble members and only one surface magnetic observation with 30% observational error. Error in reconstruction can be reduced by increasing the ensemble size and number of observations. However, this parameter reconstruction has been found to be sensitive to locations from where observational data are taken. While assimilation of low-latitudes' surface poloidal magnetic field data can produce good reconstruction, medium frequency oscillations appear in time-series of reconstructed flow-speed if tachocline toroidal field data are assimilated. These oscillations occur primarily because tachocline toroidal fields change very little during an assimilation interval taken to be 15 days, due to changes in meridional flow. A Babcock-Leighton dynamo model's response time to changes in meridional flow-speed is a few months. We show here that rms error in reconstruction can be significantly reduced if model's response time is taken into consideration in assimilation of tachocline toroidal field data.
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