| 1. |
- Blecki, J., Savin, S., Rothkaehl, H., Stasiewicz, K., Wronowski, R., Nemecek, Z., Safrankowa, J. and Kudela, K.
(författare)
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Wave-particle interaction in the polar cusp.
- 2001
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Ingår i: Les Woolliscroft Memorial Conference Sheffield Space Plasma Meeting: Multipoint Measurements versus Theory. Proceedings (SP-492). ; , s. 87-
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This paper presents the review of the observations of the low frequency plasma waves together with plasma particles which were done by Interball 1 Magion-4 subsatellite to Interball 1 and Freja satellites in the different cusp regions. The detailed study
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| 2. |
- Gustafsson, Georg, et al.
(författare)
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First results of electric field and density observations by Cluster EFW based on initial months of operation
- 2001
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Ingår i: Annales Geophysicae. - : Copernicus GmbH. - 0992-7689 .- 1432-0576. ; 19:12-okt, s. 1219-1240
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Tidskriftsartikel (refereegranskat)abstract
- Highlights are presented from studies of the electric field data from various regions along the CLUSTER orbit. They all point towards a very high coherence for phenomena recorded on four spacecraft that are separated by a few hundred kilometers for structures over the whole range of apparent frequencies from I mHz to 9 kHz. This presents completely new opportunities to study spatial-temporal plasma phenomena from the magnetosphere out to the solar wind. A new probe environment was constructed for the CLUSTER electric field experiment that now produces data of unprecedented quality. Determination of plasma flow in the solar wind is an example of the capability of the instrument.
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| 3. |
- Gustafsson, G, et al.
(författare)
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The electric field and wave experiment for the Cluster mission
- 1997
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Ingår i: Space Science Reviews. - 0038-6308 .- 1572-9672. ; 79, s. 137-156
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Tidskriftsartikel (refereegranskat)abstract
- The electric-field and wave experiment (EFW) on Cluster is designed to measure the electric-field and density fluctuations with sampling rates up to 36 000 samples s(-1). Langmuir probe sweeps can also be made to determine the electron density and temperature. The instrument has several important capabilities. These include (1) measurements of quasi-static electric fields of amplitudes lip to 700 mV m(-1) with high amplitude and time resolution, (2) measurements over short periods of time of up to five simualtaneous waveforms (two electric signals and three magnetic signals from the seach coil magnetometer sensors) of a bandwidth of 4 kHz with high time resolution, (3) measurements of density fluctuations in four points with high time resolution. Among the more interesting scientific objectives of the experiment are studies of nonlinear wave phenomena that result in acceleration of plasma as well as large- and small-scale interferometric measurements. By using four spacecraft for large-scale differential measurements and several Langmuir probes on one spacecraft for small-scale interferometry, it will be possible to study motion and shape of plasma structures on a wide range of spatial and temporal scales. This paper describes the primary scientific objectives of the EFW experiment and the technical capabilities of the instrument.
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| 4. |
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| 5. |
- Bellan, PM, et al.
(författare)
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Fine-scale cavitation of ionospheric plasma caused by inertial Alfven wave ponderomotive force
- 1998
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Ingår i: PHYSICAL REVIEW LETTERS. - : AMERICAN PHYSICAL SOC. - 0031-9007. ; 80:16, s. 3523-3526
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Tidskriftsartikel (refereegranskat)abstract
- Deep, very narrow magnetic-field-aligned density depletions were observed by the Freja spacecraft during auroral oval crossings. These cavities have perpendicular width of the order of the Electron skin depth c/omega(pe) and are associated with low-freque
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| 6. |
- Gustafsson, G, et al.
(författare)
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The electric field and wave experiment for the Cluster mission
- 1997
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Ingår i: SPACE SCIENCE REVIEWS. - : KLUWER ACADEMIC PUBL. - 0038-6308. ; 79:1-2, s. 137-156
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Tidskriftsartikel (refereegranskat)abstract
- The electric-field and wave experiment (EFW) on Cluster is designed to measure the electric-field and density fluctuations with sampling rates up to 36 000 samples s(-1). Langmuir probe sweeps can also be made to determine the electron density and tempera
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| 7. |
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| 8. |
- Khotyaintsev, Y., et al.
(författare)
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Electron energization by Alfven waves : Freja and sounding rocket observations
- 2000
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Ingår i: Physica scripta. T. - 0281-1847. ; T84, s. 151-153
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Tidskriftsartikel (refereegranskat)abstract
- Recent sounding rockets observations highlight some space-time ambiguities in phenomena taking place in the auroral ionosphere, previously observed by the Freja spacecraft. Field aligned electron populations with energies from a few tens of eV to a few keV streaming through cold background plasma are usually observed in the auroral zone in association with strongly nonlinear electromagnetic perturbations. Simultaneous observations of bursty Langmuir emissions indicate the unstable character of these plasma distributions. A detailed analysis shows that the electromagnetic perturbations take the form of quasi-stationary nonlinear spatial structures related to inertial Alfven waves. We suggest that inhomogeneous altitude distribution of the parallel electric field of these structures due to ionospheric density gradientis responsible for the observed electron distributions.
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| 9. |
- Khotyaintsev, Y, et al.
(författare)
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Electron Energization by Alfvén Waves: Freja and Sounding Rocket Observations
- 2000
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Ingår i: Physica Scripta. - 0281-1847. ; T84, s. 151-
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Tidskriftsartikel (refereegranskat)abstract
- An alternative form of the nonrelativistic permittivity tensor for a homogeneous magnetized plasma in thermal equilibrium is derived in the linear approximation. The derivation follows the lines of Trubnikov's derivation of the relativistic permittivity t
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| 10. |
- Khotyaintsev, Y, et al.
(författare)
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Langmuir wave structures registered by FREJA: Analysis and modeling.
- 2001
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Ingår i: Advances in Space Research. ; 28:11, s. 1649-1654
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Tidskriftsartikel (refereegranskat)abstract
- A large set of observations of Langmuir emissions generated by super-thermal electron beams in the topside polar ionosphere has been obtained during the recent FREJA mission. Langmuir emissions appeared as a chain of strongly modulated wave packets; in ma
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| 11. |
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| 12. |
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| 13. |
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| 14. |
- Popielawska, B., et al.
(författare)
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An imprint of the quiet plasma sheet structure at the orbit of viking : Magnetosphere without substorms
- 1996
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Ingår i: European Space Agency, (Special Publication) ESA SP. - 0379-6566. ; :389, s. 133-139
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Tidskriftsartikel (refereegranskat)abstract
- We present a study of the plasma sheet structure as seen on VIKING during prolonged periods of magnetic quiescence. The ion and electron spectrograms, the electric field data and field-aligned current signatures in the magnetic field data are examined. A special attention is paid to cases when the Low Latitude Boundary Layer-like plasma is seen deep in the nightside at latitudes which apparently map to close geocentric distances as it implies an exotic plasma circulation in the tail. An attempt has been made to infer from VIKING data how the quiet plasma sheet is formed, whether it originates mainly from the mantle source via the interaction with the distant tail current sheet or whether the lateral transport of the Low Latitude Boundary Layer (LLBL) from the tail flanks (with essentially adiabatic particle motion) takes place followed by the sunward convection in the central part of the near-Earth tail. The VIKING plasma and electric field data suggest that the last mechanism is decisive for plasma sheet structuring during prolonged periods of northward IMF.
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| 15. |
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| 16. |
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| 17. |
- Stasiewicz, K., et al.
(författare)
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Acceleration of solar wind ions to 1 MeV by electromagnetic structures upstream of the Earth's bow shock
- 2013
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Ingår i: Europhysics letters. - : IOP Publishing. - 0295-5075 .- 1286-4854. ; 102:4, s. 49001-
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Tidskriftsartikel (refereegranskat)abstract
- We present measurements from the ESA/NASA Cluster mission that show in situ acceleration of ions to energies of 1MeV outside the bow shock. The observed heating can be associated with the presence of electromagnetic structures with strong spatial gradients of the electric field that lead to ion gyro-phase breaking and to the onset of chaos in ion trajectories. It results in rapid, stochastic acceleration of ions in the direction perpendicular to the ambient magnetic field. The electric potential of the structures can be compared to a field of moguls on a ski slope, capable of accelerating and ejecting the fast running skiers out of piste. This mechanism may represent the universal mechanism for perpendicular acceleration and heating of ions in the magnetosphere, the solar corona and in astrophysical plasmas. This is also a basic mechanism that can limit steepening of nonlinear electromagnetic structures at shocks and foreshocks in collisionless plasmas.
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| 18. |
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| 19. |
- Stasiewicz, K, et al.
(författare)
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Cavity resonators and Alfven resonance cones observed on Freja
- 1997
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Ingår i: Journal of Geophysical Research - Space Physics. - 2169-9380 .- 2169-9402. ; 102:A2, s. 2565-2575
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Tidskriftsartikel (refereegranskat)abstract
- Multiresolution wavelet analysis of magnetic field, electric field, and plasma density records taken on Freja during strong auroral events shows evidence for cavity Alfven resonators in the topside ionosphere. The cavity (or transverse) resonators consist of standing perpendicular wave modes which are trapped inside plasma cavities of different perpendicular scales. The smallest size cavities have perpendicular widths comparable to the electron skin depth, lambda(s) = 2 pi c/omega(pe), and are presumably associated with the resonance cones of Alfven waves launched by a magnetospheric source. The Alfven resonance cones (ARCs) carry intense field-aligned currents, support strong parallel electric fields and represent discharge and heating channels for auroral particles. We have made a detailed analysis of the electromagnetic properties of two singular auroral structures associated with ARCs. Field-aligned currents at the resonance structures reach intensities of 100-300 rho Am-2 in the upward and downward directions and are carried mainly by cold ionospheric plasma in both directions. The parallel electric field of ARCs is observed at amplitudes up to 100 mV/m, which is 2 orders of magnitude larger than expected for the unbounded Alfven waves. Field-aligned electron beams accelerated inside ARCs are observed to drive Langmuir waves with parallel electric field occasionally exceeding 1 V/m. One of the analyzed ARC structures has electromagnetic and particle properties characteristic of ''black aurora'' with electric field diverging from the center of the cavity; the other has converging electric field.
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| 20. |
- Stasiewicz, K, et al.
(författare)
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Cavity resonators and Alfven resonance cones observed on Freja
- 1997
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Ingår i: JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS. - : AMER GEOPHYSICAL UNION. ; 102:A2, s. 2565-2575
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Tidskriftsartikel (refereegranskat)abstract
- Multiresolution wavelet analysis of magnetic field, electric field, and plasma density records taken on Freja during strong auroral events shows evidence for cavity Alfven resonators in the topside ionosphere. The cavity (or transverse) resonators consist
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| 21. |
- Stasiewicz, K, et al.
(författare)
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Density depletions and current singularities observed by Freja
- 1998
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Ingår i: JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS. - : AMER GEOPHYSICAL UNION. ; 103:A3, s. 4251-4260
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Tidskriftsartikel (refereegranskat)abstract
- High time resolution data collected by the Freja spacecraft in the topside ionosphere (h similar to 1500 km) reveal that the "low-frequency turbulence" observed commonly below the ion gyrofrequency consists of a large number of coherent plasma structures
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| 22. |
- Stasiewicz, K, et al.
(författare)
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Identification of widespread turbulence of dispersive Alfven waves
- 2000
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Ingår i: Geophysical Research Letters. - 0094-8276. ; 27, s. 173-176
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a comprehensive review of dispersive Alfven waves in space and laboratory plasmas. We start with linear properties of Alfven waves and show how the inclusion of ion gyroradius, parallel electron inertia, and finite frequency effects mo
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| 23. |
- Stasiewicz, K, et al.
(författare)
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Multiscale current structures observed by Freja
- 1998
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Ingår i: JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS. - : AMER GEOPHYSICAL UNION. ; 103:A3, s. 4315-4325
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Tidskriftsartikel (refereegranskat)abstract
- Multiscale structure of field-aligned currents and plasma density records are analyzed with multiresolution wavelet technique. We show that field-aligned currents measured by Freja in the auroral region have a spectrum of scales from similar to 500 km dow
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| 24. |
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| 25. |
- Stasiewicz, K, et al.
(författare)
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Parametric instabilities of Langmuir waves observed by Freja
- 1996
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Ingår i: JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS. - : AMER GEOPHYSICAL UNION. - 0148-0227. ; 101:A10, s. 21515-21525
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Tidskriftsartikel (refereegranskat)abstract
- We have analyzed complete spectrum of waves (0-4 MHz) and electron distributions during events of modulated Langmuir waves observed by Freja in the topside polar ionosphere. Modulated Langmuir waves are observed with amplitudes 1-1000 mV/m in association
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| 26. |
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| 27. |
- Stasiewicz, K., Seyler, C.E., Mozer, F.S., Gustafsson, G., Pickett, J. and Popielawska, B.
(författare)
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Magnetic bubbles and kinetic Alfven waves in the high-latitude magnetopause boundary.
- 2001
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Ingår i: Journal of Geophysical Research. ; 106:A12, s. 29503-
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Tidskriftsartikel (refereegranskat)abstract
- We present a detailed analysis of magnetic bubbles observed by the Polar satellite in the high-latitude magnetopause boundary. The bubbles which represent holes or strong depressions (up to 98%) of the ambient magnetic field axe filled with heated solar w
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| 28. |
- Stasiewicz, K, et al.
(författare)
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Small Scale Alfvenic structure in the aurora
- 2000
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Ingår i: Space Science Reviews. - : KLUWER ACADEMIC PUBL. - 0038-6308. ; 92:3-4, s. 423-533
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a comprehensive review of dispersive Alfven waves in space and laboratory plasmas. We start with linear properties of Alfven waves and show how the inclusion of ion gyroradius, parallel electron inertia, and finite frequency effects mo
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| 29. |
- Stasiewicz, K., et al.
(författare)
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Stochastic ion heating by orbit chaotization on electrostatic waves and nonlinear structures
- 2000
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Ingår i: Physica scripta. T. - 0281-1847. ; T84, s. 60-63
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate that satellite observations of intense transverse ion energization could be explained by stochastic ion heating on short perpendicular wavelength electrostatic waves and structures produced by the decay of dispersive Alfven waves (DAW) This mechanism is related to the chaotization of ion orbits which leads to strong stochastic heating when the electric field gradient fulfills the inequality partial derivative E-x/partial derivative x > Omega B-0 (here Omega is the ion gyrofrequency and B-0 is the ambient magnetic field). We also show that the energy sourer for this process is provided from dissipation of the Poynting flux of DAW. which appear to form an energy cascade from large scales lambda(perpendicular to) similar to kilometers down to lambda(perpendicular to) similar to 50 m where the dissipation through the ion heating is observed.
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| 30. |
- Stasiewicz, K, et al.
(författare)
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Stochastic ion heating by orbit chaotization on electroststic waves and nonlinear structures
- 2000
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Ingår i: Physica Scripta. - : ROYAL SWEDISH ACAD SCIENCES. - 0281-1847. ; T84, s. 60-63
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate that satellite observations of intense transverse ion energization could be explained by stochastic ion heating on short perpendicular wavelength electrostatic waves and structures produced by the decay of dispersive Alfven waves (DAW) This
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