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Foreshock waves as observed in energetic ion flux
Author(s) -
Petrukovich A. A.,
Chugunova O. M.,
Inamori T.,
Kudela K.,
Stetiarova J.
Publication year - 2017
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1002/2016ja023693
Subject(s) - foreshock , physics , solar wind , amplitude , flux (metallurgy) , geophysics , waveform , ion , computational physics , atmospheric sciences , plasma , geology , seismology , optics , nuclear physics , aftershock , materials science , quantum mechanics , voltage , metallurgy
Abstract Oscillations of energetic ion fluxes with periods 10–100 s are often present in the Earth's foreshock. Detailed analysis of wave properties with Time History of Events and Macroscale Interactions during Substorms data and comparisons with other data sets confirm that these oscillations are the previously unnoticed part of well‐known “30 s” waves but are observed mainly for higher‐speed solar wind. Simultaneous magnetic oscillations have similar periods, large amplitudes, and nonharmonic unstable waveforms or shocklet‐type appearance, suggesting their nonlinearity, also typical for high solar wind speed. Analysis of the general foreshock data set of Interball project shows that the average flux of the backstreaming energetic ions increases more than 1 order of magnitude, when solar wind speed increases from 400 to 500 km/s.