A Census of Plasma Waves and Structures Associated With an Injection Front in the Inner Magnetosphere

Abstract

Now that observations have conclusively established that the inner magnetosphere is abundantly populated with kinetic electric field structures and nonlinear waves, attention has turned to quantifying the ability of these structures and waves to scatter and accelerate inner magnetospheric plasma populations. A necessary step in that quantification is determining the distribution of observed structure and wave properties (e.g., occurrence rates, amplitudes, and spatial scales). Kinetic structures and nonlinear waves have broadband signatures in frequency space, and consequently, high‐resolution time domain electric and magnetic field data are required to uniquely identify such structures and waves as well as determine their properties. However, most high‐resolution fields data are collected with a strong bias toward high‐amplitude signals in a preselected frequency range, strongly biasing observations of structure and wave properties. In this study, an ∼45 min unbroken interval of 16,384 samples/s field burst data, encompassing an electron injection event, is examined. This data set enables an unbiased census of the kinetic structures and nonlinear waves driven by this electron injection, as well as determination of their “typical” properties. It is found that the properties determined using this unbiased burst data are considerably different than those inferred from amplitude‐biased burst data, with significant implications for wave‐particle interactions due to kinetic structures and nonlinear waves in the inner magnetosphere.

Unified View of Nonlinear Wave Structures Associated with Whistler-Mode Chorus

“…The electron cyclotron frequency ω ce is equal to 0.1 ω pe . This uniform background magnetic field is used since the excitation of the nonlinear wave structures is typically observed in the region around the magnetic equator [9,16].…”

Statistical Occurrence and Distribution of High‐Amplitude Whistler Mode Waves in the Outer Radiation Belt

“…These large-amplitude whistler mode waves interact differently with electrons than their lower-amplitude counterparts, potentially resulting in trapping, rapid energization or de-energization, and pitch angle scattering (Bortnik et al, 2008;Cattell et al, 2008;Kellogg et al, 2010;Kersten et al, 2011;Omura et al, 2008Omura et al, , 2013Summers & Omura, 2007). Malaspina et al (2018) showed that even moderate-amplitude whistler mode waves could demonstrate nonlinear distortions in their waveforms, and the relative magnitude of this distortion is amplitude dependent.…”

Simultaneous Multispacecraft Probing of Electron Phase Space Holes

“…EHs in the auroral region (Ergun et al, ; Franz et al, ), inner magnetosphere (Malaspina et al, ; Vasko et al, ), and flow braking region (Ergun et al, ) exhibit noticeable perpendicular electric fields with essentially unipolar profiles. The perpendicular electric fields indicate that EHs are intrinsically three‐dimensional structures localized in directions perpendicular to the local magnetic field.…”