| 1. |
- Bale, S. D., et al.
(författare)
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The FIELDS Instrument Suite for Solar Probe Plus
- 2016
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Ingår i: Space Science Reviews. - : Springer Science and Business Media LLC. - 0038-6308 .- 1572-9672. ; 204:1-4, s. 49-82
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Forskningsöversikt (refereegranskat)abstract
- NASA's Solar Probe Plus (SPP) mission will make the first in situ measurements of the solar corona and the birthplace of the solar wind. The FIELDS instrument suite on SPP will make direct measurements of electric and magnetic fields, the properties of in situ plasma waves, electron density and temperature profiles, and interplanetary radio emissions, amongst other things. Here, we describe the scientific objectives targeted by the SPP/FIELDS instrument, the instrument design itself, and the instrument concept of operations and planned data products.
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| 2. |
- Cattell, C., et al.
(författare)
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Dayside response of the magnetosphere to a small shock compression : Van Allen Probes, Magnetospheric MultiScale, and GOES-13
- 2017
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Ingår i: Geophysical Research Letters. - : AMER GEOPHYSICAL UNION. - 0094-8276 .- 1944-8007. ; 44:17, s. 8712-8720
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Tidskriftsartikel (refereegranskat)abstract
- Observations from Magnetospheric MultiScale (similar to 8 Re) and Van Allen Probes (similar to 5 and 4 Re) show that the initial dayside response to a small interplanetary shock is a double-peaked dawnward electric field, which is distinctly different from the usual bipolar (dawnward and then duskward) signature reported for large shocks. The associated ExB flow is radially inward. The shock compressed the magnetopause to inside 8 Re, as observed by Magnetospheric MultiScale (MMS), with a speed that is comparable to the ExB flow. The magnetopause speed and the ExB speeds were significantly less than the propagation speed of the pulse from MMS to the Van Allen Probes and GOES-13, which is consistent with the MHD fast mode. There were increased fluxes of energetic electrons up to several MeV. Signatures of drift echoes and response to ULF waves also were seen. These observations demonstrate that even very weak shocks can have significant impact on the radiation belts. Plain Language Summary Very fast moving clouds of charged particles are ejected from the Sun when it is active. Shock waves often develop at the cloud front as it plows through the solar wind. When the shock hits the Earth's magnetic field, it can push the Earth's magnetic shield inside the distance where many communication and weather satellites orbit. The energy associated with the shock can also very rapidly increase the energy of electrons trapped in the Earth's magnetic field in the Van Allen Radiation belts. These electrons can damage satellites. We have used four satellites arrayed at different locations on the dayside of the Earth's magnetic field to show, for the first time, that small shocks have a different effect than the large shocks that are usually studied but that even small shocks can produce relativistic electrons.
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| 5. |
- Pedersen, A., et al.
(författare)
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Quasistatic electric field measurements with spherical double probes on the GEOS and ISEE satellites
- 1984
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Ingår i: Space Science Reviews. - 0038-6308 .- 1572-9672. ; 37, s. 269-312
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Tidskriftsartikel (refereegranskat)abstract
- Spherical double probes for measurements of electric fields on the GEOS-1, GEOS-2, and ISEE-1 satellites are described. An essential feature of these satellites is their conductive surfaces which eliminate errors due to differential charging and enable meaningful diagnostic experiments to be carried out. The result of these experiments is a good understanding of interactions between the plasma, the satellite and the probes, including photo-electron emission on satellite and probes. Electric field measurements are compared with measurements of plasma drift perpendicular to the magnetic field in the solar wind and the magnetosphere and the error bar for the absolute values of the electric field is found to be in the range ±(0.5-1.0) mV m-1 whereas relative variations can be determined with much better accuracy. A useful by-product from a spherical double probe system is the determination of satellite floating potential which is related to the plasma electron flux. This measurement allows high time resolution studies of boundary crossings. Examples of electric field measurements, which reflect the recent scientific results, are given for different regions of the magnetosphere from the bow shock, the inner magnetosphere and the tail. Several examples of simultaneous GEOS-ISEE observations are described. © 1984 D. Reidel Publishing Company.
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| 6. |
- Sung, S. -K, et al.
(författare)
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Simultaneous ground-based and satellite observations of Pc5 geomagnetic pulsations : A case study using multipoint measurements
- 2006
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Ingår i: Earth Planets and Space. - 1343-8832 .- 1880-5981. ; 58:7, s. 873-883
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Tidskriftsartikel (refereegranskat)abstract
- Pc5 pulsations with a latitude-independent frequency of similar to 2.8 rnHz (period similar to 6 min) were observed with ground-based magnetometers in the morning sector (0700-1000 local time) from 0730 to 0810 UT, April 29, 2001. The pulsations exhibited an amplitude peak and a similar to 180 degrees phase change at similar to 67 degrees geomagnetic latitude. A vortex structure of the equivalent ionospheric current system was also observed centered at the geomagnetic latitude between 67 degrees and 71 degrees. During the Pc5 event, the Polar spacecraft was located near the morningside magnetic equator and crossed magnetic field lines conjugate to the ground stations at which the pulsations were strong. Polar observed similar to 2.8 mHz pulsations in the radial electric field and compressional magnetic field components. Since toroidal mode Alfven waves in the magnetosphere are characterized by an electric field perturbation in the radial direction, the simultaneous presence of pulsations in both components indicates that a field line resonance (FLR) was driven by compressional pulsations. The ground H component at the station conjugate to Polar and the radial electric field perturbation at Polar oscillated with a great similarity without a phase delay. From an analysis of the ground-satellite data, we suggest that the ground perturbations are associated with toroidal mode Alfven waves rather than compressional mode propagating across magnetic field lines. In addition, we discuss the source of the compressional perturbations observed at Polar using solar wind and geosynchronous data.
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