Journal cover Journal topic
Annales Geophysicae Sun, Earth, planets, and planetary systems An interactive open-access journal of the European Geosciences Union
Ann. Geophys., 36, 781-791, 2018
https://doi.org/10.5194/angeo-36-781-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
Regular paper
23 May 2018
Van Allen Probes observation of plasmaspheric hiss modulated by injected energetic electrons
Run Shi1, Wen Li1, Qianli Ma2,1, Seth G. Claudepierre3, Craig A. Kletzing4, William S. Kurth4, George B. Hospodarsky4, Harlan E. Spence5, Geoff D. Reeves6, Joseph F. Fennell3, J. Bernard Blake3, Scott A. Thaller7, and John R. Wygant7 1Center for Space Physics, Boston University, Boston, Massachusetts, USA
2Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, Los Angeles, California, USA
3Space Science Department, The Aerospace Corporation, El Segundo, California, USA
4Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa, USA
5Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, New Hampshire, USA
6Space Science and Applications Group, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
7School of Physics and Astronomy, University of Minnesota, Twin Cities, Minneapolis, Minnesota, USA
Abstract. 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 (L  >   ∼  5.5) is locally amplified. Meanwhile, Van Allen Probe A observed hiss emission at lower L shells ( <  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 L shells.
Citation: Shi, R., Li, W., Ma, Q., Claudepierre, S. G., Kletzing, C. A., Kurth, W. S., Hospodarsky, G. B., Spence, H. E., Reeves, G. D., Fennell, J. F., Blake, J. B., Thaller, S. A., and Wygant, J. R.: Van Allen Probes observation of plasmaspheric hiss modulated by injected energetic electrons, Ann. Geophys., 36, 781-791, https://doi.org/10.5194/angeo-36-781-2018, 2018.
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