Van Allen Probes observation of plasmaspheric hiss modulated by injected energetic electrons

Academic Article

Abstract

  • <p><strong>Abstract.</strong> Plasmaspheric hiss was observed by Van Allen Probe B in association with energetic electron injections in the outer plasmasphere. The energy of injected electrons coincides with the minimum resonant energy calculated for the observed hiss wave frequency. Interestingly, the variations in hiss wave intensity, electron flux and ultra low frequency (ULF) wave intensity exhibit remarkable correlations, while plasma density is not correlated with any of these parameters. Our study provides direct evidence for the first time that the injected anisotropic electron population, which is modulated by ULF waves, modulates the hiss intensity in the outer plasmasphere. This also implies that the plasmaspheric hiss observed by Van Allen Probe B in the outer plasmasphere (<span class="inline-formula"><i>L</i></span><span class="thinspace"></span><span class="inline-formula">&amp;gt;</span><span class="thinspace"></span><span class="inline-formula">∼</span><span class="thinspace"></span>5.5) is locally amplified. Meanwhile, Van Allen Probe A observed hiss emission at lower <span class="inline-formula"><i>L</i></span> shells (<span class="inline-formula">&amp;lt;</span><span class="thinspace"></span>5), which was not associated with electron injections but primarily modulated by the plasma density. The features observed by Van Allen Probe A suggest that the observed hiss deep inside the plasmasphere may have propagated from higher <span class="inline-formula"><i>L</i></span> shells.</p>
  • Authors

  • Shi, Run
  • Li, Wen
  • Ma, Qianli
  • Claudepierre, Seth G
  • Kletzing, Craig A
  • Kurth, William S
  • Hospodarsky, George B
  • Spence, Harlan
  • Reeves, Geoff D
  • Fennell, Joseph F
  • Blake, J Bernard
  • Thaller, Scott A
  • Wygant, John R
  • Status

    Publication Date

  • May 23, 2018
  • Published In

    Digital Object Identifier (doi)

    Start Page

  • 781
  • End Page

  • 791
  • Volume

  • 36
  • Issue

  • 3