A geomagnetic storm on January 17, 2013, provided unique observations that finally resolved a long-standing scientific problem. For decades, scientists had asked how particles hitting Earth’s magnetosphere were lost. A likely mechanism involved certain electromagnetic waves scattering particles into the Earth’s atmosphere. Unique observations provided detailed information throughout the belts on the energy spectrum and pitch angle distribution of electrons up to ultra-relativistic energies. We showed that although relativistic electrons are enhanced, ultra-relativistic electrons become depleted and distributions of particles showed very clear telltale signatures of electromagnetic ion cyclotron (EMIC) wave-induced loss.
Our planet is nestled in the center of the Van Allen belts, where high-energy particles are trapped by Earth’s magnetic field pic.twitter.com/fFscCpUcF6
— NASA (@NASA) 28 September 2016 г.
The study was published in Nature Comminications: Yuri Y. Shprits, Alexander Y. Drozdov, Maria Spasojevic, Adam C. Kellerman, Maria E. Usanova, Mark J. Engebretson, Oleksiy V. Agapitov, Irina S. Zhelavskaya, Tero J. Raita, Harlan E. Spence, Daniel N. Baker, Hui Zhu & Nikita A. Aseev (2016), Wave-induced loss of ultra-relativistic electrons in the Van Allen radiation belts., Nature Communications, 7, 12883, doi:10.1038/NCOMMS12883