Modulated Upper-Hybrid Waves Coincident With Lower-Hybrid Waves in the Cusp

C. Moser; J. LaBelle; R. Roglans; J. W. Bonnell; I. H. Cairns; C. Feltman; C. A. Kletzing; S. Bounds; R. P. Sawyer; S. A. Fuselier

doi:10.1029/2021JA029590

Back

Modulated Upper-Hybrid Waves Coincident With Lower-Hybrid Waves in the Cusp

Journal article

Open access

Peer reviewed

Modulated Upper-Hybrid Waves Coincident With Lower-Hybrid Waves in the Cusp

C. Moser, J. LaBelle, R. Roglans, J. W. Bonnell, I. H. Cairns, C. Feltman, C. A. Kletzing, S. Bounds, R. P. Sawyer and S. A. Fuselier

Journal of geophysical research. Space physics, Vol.126(9), e2021JA029590

09/01/2021

DOI: 10.1029/2021JA029590

Files and links (1)

url

https://doi.org/10.1029/2021JA029590View

Published (Version of record) Open Access

Abstract

During the Twin Rockets to Investigate Cusp Electrodynamics (TRICE-2) High-Flyer rocket's passage through the cusp the high frequency (HF) radio wave receiver observed three intervals of banded upper-hybrid (UH) waves. The bands begin at the UH frequency (similar to 1.2-1.3 MHz), descending to as low as 1.1 MHz, with amplitudes of hundreds of mV/m. The spacing of the bands are similar to 4.5-6 kHz and the number of bands ranges from 3 to 10. Simultaneously, the very low frequency (VLF) radio wave receiver observed lower-hybrid (LH) waves with amplitudes ranging from 1 to 10 mV/m and frequencies of 4.5-6 kHz. Slight variations of the spacings of the bands in the UH waves were closely correlated with variations in the LH peak frequencies. Two possible wave-wave interactions are explored to explain this phenomenon: decay of an UH wave into a lower frequency UH wave and a LH wave, and coalescence of independent UH waves and LH waves that spawn UH waves. Using a dispersion relation calculator with electron and ion distribution functions based off those observed by the particle instruments suggests that UH waves, and to a lesser degree LH waves, can be excited by linear instabilities. Kinematic analysis of the waves dispersion relations and the wave matching conditions show that wave-wave interactions linking UH and LH modes are possible through either decay or coalescence. This analysis along with comparisons of the energy densities of the waves, and the ratio of their occupation numbers suggest that the decay process is more likely than coalescence.

Physical Sciences

Astronomy & Astrophysics

Science & Technology

Details

Title: Subtitle: Modulated Upper-Hybrid Waves Coincident With Lower-Hybrid Waves in the Cusp
Creators: C. Moser - Dartmouth College
J. LaBelle - Dartmouth College
R. Roglans - University of California, Berkeley
J. W. Bonnell - University of California, Berkeley
I. H. Cairns - University of Sydney
C. Feltman - University of Iowa
C. A. Kletzing - University of Iowa
S. Bounds - University of Iowa
R. P. Sawyer - The University of Texas at San Antonio
S. A. Fuselier - The University of Texas at San Antonio
Resource Type: Journal article
Publication Details: Journal of geophysical research. Space physics, Vol.126(9), e2021JA029590
Publisher: Amer Geophysical Union
DOI: 10.1029/2021JA029590
ISSN: 2169-9380
eISSN: 2169-9402
Number of pages: 17
Grant note: NNX17AF92G / NASA; National Aeronautics & Space Administration (NASA) NNX15AL08G / TRICE-2 mission grant
Language: English
Date published: 09/01/2021
Academic Unit: Physics and Astronomy
Record Identifier: 9984429030702771

Metrics

5 Record Views

3 Times Cited - Web of Science