Science Daily December 9, 2021
Electromagnetic ion cyclotron waves (EMIC waves) are an important class of EM wave in Geospace that control variations in the Geospace plasma environment. The EMIC waves are considered to propagate north to south along the geomagnetic field lines. The specific spatial size of the EMIC wave source region and the 3D aspect of how the propagation path is formed from space to ground are yet to be elucidated. An international team of researchers (Japan, USA – University of Colorado, University of Minnesota, Los Alamos National Laboratory, Canada) investigated the growth and propagation of fine-structured EMIC waves observed simultaneously by two spacecraft and two ground stations. The two spacecraft orbited along the same field line, and they measured the same fine-structured EMIC waves in different geomagnetic latitude regions. The same EMIC waves were observed at the two ground stations located near the magnetic footprints of the two spacecraft. They found that the periodic growth of the observed EMIC waves was associated with the time-varying electron density irregularity in the midlatitude region. They also analyzed the spatial scale of the observed EMIC waves and their contribution to the thermal ion heating…read more. Open Access TECHNICAL ARTICLEÂ
Dynamic wave-power spectra from 00:40–02:40 UT on April 18, 2019… Credit: Geophysical Research Letters, 10 November 2021Â