Fine Structure of Chorus Wave Packets: Comparison Between Observations and Wave Generation Models. Issue 8 (20th August 2021)

• Record Type: Journal Article
• Authors: Zhang, X.‐J.; Demekhov, A. G.; Katoh, Y.; Nunn, D.; Tao, X.; Mourenas, D.; Omura, Y.; Artemyev, A. V.; Angelopoulos, V.
• Is Part Of: Journal of geophysical research. Volume 126:Issue 8(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-08-20
• Subjects: chorus wave packets -- nonlinear generation models -- frequency sweep rates -- wave packet size -- data model comparison -- Van Allen Probes; Magnetospheric physics -- Periodicals; Space environment -- Periodicals; Cosmic physics -- Periodicals; Planets -- Atmospheres -- Periodicals; Heliosphere (Astrophysics) -- Periodicals; Geophysics -- Periodicals; 523.01
• DOI: 10.1029/2021JA029330
• Languages: English
• ISSNs: 2169-9380

Abstract

Abstract: Intense lower band chorus waves are ubiquitous in the inner magnetosphere. Their properties have been modeled by various codes and investigated using measurements of many spacecraft missions. This study aims to compare simulated and observed properties of chorus waves. We present detailed comparisons between results from four different codes of nonlinear chorus wave generation and statistical observations from satellites, focusing on the fine structure of such chorus waves. We show that simulations performed with these different codes well reproduce the observed wave packet characteristics, although in somewhat complementary parameter domains as concerns wave packets sizes, amplitudes, and frequency sweep rates. In particular, simulations generate both the frequently observed short wave packets with high positive and negative frequency sweep rates, and the more rare long and intense packets with mainly rising tones. Moreover, simulations reproduce quantitatively both the increase of the size of the observed chorus wave packets with their peak amplitude, and the fast decrease of their frequency sweep rate as their size increases. This confirms the reliability of the main existing codes for accurately modeling chorus wave generation, although we find that initial conditions should be carefully selected to reproduce a given parameter range. Key Points: Four different codes of chorus wave nonlinear generation well reproduce the observed wave packet characteristics The simulations recover complementary domains of observed wave packets sizes, amplitudes, and frequency sweep rates The simulations reproduce the observed short wave packets with high positive and negative frequency sweep rates