Open AccessProton precipitation during magnetic storms in August through November 1998
Author(s) -
Walt M.,
Voss H. D.
Publication year - 2004
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2003ja010083
Subject(s) - geomagnetic storm , storm , ring current , precipitation , proton , pitch angle , atmospheric sciences , cyclotron , ion , physics , ionosphere , polar , geophysics , geology , magnetosphere , magnetic field , meteorology , earth's magnetic field , nuclear physics , astronomy , quantum mechanics
High angular resolution measurements of 155 keV protons were made from the Polar satellite during five magnetic storms in the last half of 1998. Proton precipitation was detected during all the storms studied, and in most cases protons were scattered deep into the loss cone. In one case of strong pitch angle scattering, the fluxes were isotropic for equatorial pitch angles less than 25°. During the main phases of the storms precipitation was strongest at L > 5 on the night side of the Earth, possibly due to field‐line curvature scattering of the newly injected ions. During the main and early recovery phases intense precipitation was found in the early afternoon at L > 4 where ring current models predict electromagnetic ion cyclotron waves will be generated by ring current ions. In one storm the nightside precipitation exhibited a maximum near L = 5, and this maximum moved outward during the recovery phase. In most storms the precipitation became less intense as Dst recovered.