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Disappearance, recovery and patchiness of plasmaspheric hiss following two consecutive interplanetary shocks: First results
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  • Suman Chakraborty,
  • Dibyendu Chakrabarty,
  • Geoff. D. Reeves,
  • Daniel. N. Baker,
  • Seth G. Claudepierre,
  • Aaron W. Breneman,
  • David P. Hartley,
  • Brian A. Larsen
Suman Chakraborty
Physical Research Laboratory, Gujrat, India

Corresponding Author:[email protected]

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Dibyendu Chakrabarty
Physical Research Laboratory
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Geoff. D. Reeves
Space Science and Applications Group
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Daniel. N. Baker
Laboratory for Atmospheric and Space Physics
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Seth G. Claudepierre
Space Sciences Department, The Aerospace Corporation, El Segundo, California, USA
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Aaron W. Breneman
School of Physics and Astronomy, University of Minnesota, Twin Cities, Minneapolis, MN, USA
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David P. Hartley
Department of Physics and Astronomy, University of Iowa, Iowa City, IA, USA
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Brian A. Larsen
Space Science and Applications Group, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
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Abstract

We present, for the first time, a plasmaspheric hiss event observed by the Van Allen probes in response to two successive interplanetary shocks occurring within an interval of ~2 hours on December 19, 2015. The first shock arrived at 16:16 UT and caused disappearance of hiss for ~30 minutes. Significant Landau damping by suprathermal electrons followed by their gradual removal by magnetospheric compression opposed the generation of hiss causing the disappearance. Calculation of electron phase space density and linear wave growth rates showed that the shock did not change the growth rate of whistler mode waves within the core frequency range of plasmaspheric hiss (0.1 - 0.5 kHz) during this interval making conditions unfavorable for the generation of the waves. The recovery began at ~16:45 UT which is attributed to an enhancement in local plasma instability initiated by the first shock-induced substorm and additional possible contribution from chorus waves. This time, the wave growth rate peaked within the core frequency range (~350 Hz). The second shock arrived at 18:02 UT and generated patchy hiss persisting up to ~19:00 UT. It is shown that an enhanced growth rate and additional contribution from shock-induced poloidal Pc5 mode (periodicity ∼240 sec) ULF waves resulted in the excitation of hiss waves during this period. The hiss wave amplitudes were found to be additionally modulated by background plasma density and fluctuating plasmapause location. The investigation highlights the important roles of interplanetary shocks, substorms, ULF waves and background plasma density in the variability of plasmaspheric hiss.