%ANishimura, Y. [Department of Electrical and Computer Engineering and Center for Space Physics Boston University Boston MA USA, Department of Atmospheric and Oceanic Sciences University of California Los Angeles CA USA]%ANishimura, Y. [Department of Electrical and Computer Engineering and Center for Space Physics; Boston University; Boston MA USA; Department of Atmospheric and Oceanic Sciences; University of California; Los Angeles CA USA]%ABortnik, J. [Department of Atmospheric and Oceanic Sciences University of California Los Angeles CA USA]%ABortnik, J. [Department of Atmospheric and Oceanic Sciences; University of California; Los Angeles CA USA]%ALi, W. [Department of Atmospheric and Oceanic Sciences University of California Los Angeles CA USA, Department of Astronomy and Center for Space Physics Boston University Boston MA USA]%ALi, W. [Department of Atmospheric and Oceanic Sciences; University of California; Los Angeles CA USA; Department of Astronomy and Center for Space Physics; Boston University; Boston MA USA]%AAngelopoulos, V. [Department of Earth, Planetary, and Space Sciences University of California Los Angeles CA USA]%AAngelopoulos, V. [Department of Earth, Planetary, and Space Sciences; University of California; Los Angeles CA USA]%ADonovan, E. [Department of Physics and Astronomy University of Calgary Calgary Alberta Canada]%ADonovan, E. [Department of Physics and Astronomy; University of Calgary; Calgary Alberta Canada]%ASpanswick, E. [Department of Physics and Astronomy University of Calgary Calgary Alberta Canada]%ASpanswick, E. [Department of Physics and Astronomy; University of Calgary; Calgary Alberta Canada]%BJournal Name: Journal of Geophysical Research: Space Physics; Journal Volume: 123; Journal Issue: 3; Related Information: CHORUS Timestamp: 2023-09-09 14:15:19 %D2018%IDOI PREFIX: 10.1029 %JJournal Name: Journal of Geophysical Research: Space Physics; Journal Volume: 123; Journal Issue: 3; Related Information: CHORUS Timestamp: 2023-09-09 14:15:19 %K %MOSTI ID: 10055232 %PMedium: X %TComment on “Pulsating Auroras Produced by Interactions of Electrons and Time Domain Structures” by Mozer Et Al. %XAbstract

Mozer et al. (2017,https://doi.org/10.1002/2017JA024223) suggested that time domain structures (TDSs) drive pulsating aurora (with additional contributions by kinetic Alfvén waves (KAWs)) and that chorus waves have negligible effects. In this comment, we point out that electrons scattered by TDS or KAW (dominantly at ~0.1–3 keV, <1 s modulation) cannot explain key features of pulsating aurora, which require precipitation above a few keV with a couple of tens of second modulation. Their study did not conduct quantitative evaluations of wave‐aurora correlation. The use of short burst mode data (~<10 s) may only cover a single pulse of pulsating aurora and is not suitable for examining connections to pulsating aurora. “Field‐aligned” electrons do not necessarily represent loss cone population, and their characteristic energy (hundreds of eV) is much lower than typical precipitation over pulsating aurora. By reexamining the events studied by Mozer et al., we quantitatively demonstrate that TDS and KAW are uncorrelated with pulsating aurora and that only chorus waves showed high correlations with pulsating aurora. Occasional simultaneous occurrence of TDS/KAW and pulsating aurora is found to be coincidental, because the correlation over a time scale of minutes is poor. Several auroral features analyzed in that paper are not pulsating aurora but other types of aurora. We also show that the chorus‐pulsating aurora correlation can last for 2 h or longer and can be used to highlight dynamic changes in magnetic field mapping. Chorus waves can resonate with electrons above a few keV and are in agreement with pulsating auroral properties.

%0Journal Article