On the fine inner structure of whistler mode quasiperiodic emissions

Němec, F.; Partík, Vojtěch; Parrot, M.

doi:10.1016/j.asr.2023.01.045

Cited by 2 publications

(1 citation statement)

References 57 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The event classification is thus often unclear (Sazhin & Hayakawa, 1994). In some events, high‐resolution measurements reveal an additional shorter modulation period, which roughly corresponds to the two‐hop travel time of echoing whistlers (Bespalov et al., 2010; Engebretson et al., 2004; Manninen et al., 2014; Němec et al., 2023; Smith et al., 1998).…”

Section: Introductionmentioning

confidence: 99%

Quasiperiodic Emissions: Fine Structure Corresponding to a Bouncing Wave

Němec,

Santolík,

Hospodarsky

et al. 2024

Geophysical Research Letters

View full text Add to dashboard Cite

Quasiperiodic (QP) emissions are whistler‐mode electromagnetic waves observed in the Earth's inner magnetosphere whose intensity has a nearly periodic time modulation with typical modulation periods on the order of minutes. Some events exhibit, on top of the main modulation period, an additional fine inner modulation with modulation periods on the order of seconds. We use high‐resolution multi‐component electromagnetic wave data obtained by the Van Allen Probes spacecraft to investigate one such event. Detailed wave analysis demonstrates that the fine inner modulation is due to a wave packet bouncing back and forth between the hemispheres. The presence of a density duct is important for the formation of the event, as demonstrated by the increased ratio of wave power propagating away from the equator (a tentative source region) within the duct. The main QP modulation period corresponds to the plasma number density modulation observed just outside the plasmasphere.

show abstract

Section: Introductionmentioning

confidence: 99%

Quasiperiodic Emissions: Fine Structure Corresponding to a Bouncing Wave

Němec,

Santolík,

Hospodarsky

et al. 2024

Geophysical Research Letters

View full text Add to dashboard Cite

show abstract

Magnetospheric Line Radiation: Temporal Modulation Corresponding to a Bouncing Wave

Němec,

Santolík,

Hospodarsky

et al. 2024

Geophysical Research Letters

View full text Add to dashboard Cite

Magnetospheric line radiation (MLR) is a peculiar type of whistler‐mode emissions formed by several similarly spaced spectral lines, whose frequencies may vary with time. These emissions typically occur at frequencies between about 1 and 8 kHz and are observed in both ground‐based and satellite measurements. However, their origin and source locations are not yet understood, as their detection by spacecraft instruments is challenging due to the limited frequency resolution of onboard wave measurements. We use high‐resolution multicomponent wave data obtained by the Van Allen Probes to demonstrate that, in addition to the frequency modulation, MLR events possess a temporal modulation with periods on the order of seconds, which may be related to the wave bouncing between hemispheres. Observed modulation periods are used to estimate a tentative source L‐shell. The modulation periods are shorter for events with larger frequency spacing, and the estimated source L‐shells correlate with model plasmapause locations.

show abstract

On the fine inner structure of whistler mode quasiperiodic emissions

Cited by 2 publications

References 57 publications

Quasiperiodic Emissions: Fine Structure Corresponding to a Bouncing Wave

Quasiperiodic Emissions: Fine Structure Corresponding to a Bouncing Wave

Magnetospheric Line Radiation: Temporal Modulation Corresponding to a Bouncing Wave

Contact Info

Product

Resources

About