Simultaneous observation of chorus and hiss near the plasmapause

• Published in: Journal of Geophysical Research: Space Physics
• Main Authors: Delport, B, Collier, A.B., Lichtenberger, J, Rodger, C.J., Parrot, Michel, Clilverd, Mark A., Friedel, R.H.W.
• Other Authors: School of Chemistry and Physics Durban, University of KwaZulu-Natal Durban, Afrique du Sud (UKZN), SANSA Space Science, South African National Space Agency (SANSA), Space Research Laboratory Budapest, Eötvös Loránd University (ELTE), Department of Physics Dunedin, University of Otago Dunedin, Nouvelle-Zélande, Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales Paris (CNES), British Antarctic Survey (BAS), Natural Environment Research Council (NERC), Los Alamos National Laboratory (LANL), European Project: 263218,EC:FP7:SPA,FP7-SPACE-2010-1,PLASMON(2011)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2012
• Subjects: [SDU]Sciences of the Universe [physics]; New Zealand; Marion Island
• Online Access: https://insu.hal.science/insu-01179533; https://insu.hal.science/insu-01179533/document; https://insu.hal.science/insu-01179533/file/Delport_et_al-2012-Journal_of_Geophysical_Research__Space_Physics_%281978_2012%29.pdf; https://doi.org/10.1029/2012JA017609

International audience [1] On 4 August 2010 a moderate geomagnetic storm occurred with minimum Dst of À65 nT and maximum K p of 7À. Shortly after the onset of this storm, VLF chorus was observed at Marion Island (L = 2.6). Over time the spectral structure of the chorus transformed into a hiss band spanning the same frequency range. The observation of overlapping chorus and hiss suggests that Marion Island was close to the plasmapause at the time of this event, and provides ground-based observational confirmation of the generation mechanism of plasmaspheric hiss from chorus waves outside of the plasmasphere. Chorus observations at Marion Island were not common during this period of the solar cycle and so this event was investigated in detail. The geomagnetic conditions are discussed and geosynchronous particle data and broadband data from two other stations are presented. Empirical models are employed to predict the location of the plasmapause, and its location is inferred from a knee whistler recorded at Dunedin, New Zealand. These show that Marion Island is in the vicinity of the plasmapause during the event. The event is also compared to chorus observed at similar L after the Halloween storms of 2003. The rarity of the chorus observation is quantified using DEMETER VLF data. The DEMETER data, along with the various ground based VLF measurements, allows us to infer temporal and spatial variations in the chorus source region.