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Evidence for acceleration of ions to ∼ 1 Mev by adiabatic‐like reflection at the quasi‐perpendicular Earth's bow shock
Author(s) -
Meziane K.,
Lin R. P.,
Parks G. K.,
Larson D. E.,
Bale S. D.,
Mason G. M.,
Dwyer J. R.,
Lepping R. P.
Publication year - 1999
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/1999gl900603
Subject(s) - physics , proton , atomic physics , solar wind , ion , adiabatic process , bow shock (aerodynamics) , reflection (computer programming) , bow wave , shock (circulatory) , interplanetary medium , spectral line , pitch angle , interplanetary spaceflight , shock wave , plasma , nuclear physics , geophysics , astronomy , medicine , quantum mechanics , computer science , thermodynamics , programming language
On December 6, 1994, during a CIR (Corotating Interaction Region) event, the WIND 3D‐Plasma and energetic particle experiment observed a burst (≤24 s) of 238–676 keV protons close to the electron foreshock boundary, followed by a 156–236 keV, 101–156 keV and 33–101 keV proton bursts about ∼40 s, 65 s and 85 s later, respectively. Similar dispersed bursts of helium with energies between ∼50 keV and ∼1 MeV followed the proton bursts. During this time, the IMF direction varied slowly with an almost monotonic decrease in θ Bn . The proton energy spectrum is initially peaked at ∼350 keV, and progresses to lower energies with time. The proton 3D angular distributions are peaked at ∼30° pitch‐angle, propagating away from the shock, but they are nongyrotropic. Finally, we show that the proton energy‐spectra as well as the pitch angle distribution agree quantitatively with a model of a single adiabatic reflection of the incident energetic interplanetary ions by the quasi‐perpendicular shock.