EGU2020-8520, updated on 12 Jun 2020
https://doi.org/10.5194/egusphere-egu2020-8520
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Earth’s magnetotail as the reservoir of accelerated single- and multicharged oxygen ions replenishing radiation belts

Elena Parkhomenko1, Vladimir Kalegaev1, Helmi Malova1,2, Mikhail Panasyuk2, Victor Popov1,3,4, Natalia Vlasova2, and Lev Zelenyi1
Elena Parkhomenko et al.
  • 1Space Research Institute of the RAS, Moscow, Russia
  • 2Lomonosov Moscow State University, Scobeltsyn Institute of Nuclear Physics, Moscow, Russia
  • 3Lomonosov Moscow State University, Physics Department, Moscow, Russia
  • 4National Research University «Higher School of Economics», Moscow, Russia

In this work we are studying multicharged oxygen ion acceleration during substorms in the Earth's magnetotail as the source of ring current replenishment by energetic ion population. We used measurements obtained by the CRRES spacecraft for the comparison of experimental spectra of oxygen charge state in the outer region of the ring current and proton radiation belt with model results. We present a numerical model that allows to evaluate acceleration of oxygen ions O+-O+8 in the course of two possible perturbation processes: A) passage of multiple dipolarization fronts in the magnetotail; B) passage of fronts followed by electromagnetic turbulence. It is shown that acceleration processes depend on particle charges and time scale of electric field variations. Oxygen ions O+8 with average initial energies 12 keV are accelerated efficiently during multiple dipolarization processes of type (A) and their energies increased up to 7.4 MeV, whereas ions O+1 with the same energies were energized up to 1.9 МeV. It is shown that oxygen ions O+-O+2 are able to penetrate into the ring/radiation belts region with L between L=4.5 and L=7.5 in the process of plasma transfer on dipolarization fronts. For oxygen O+-O+8 the additional acceleration mechanism is required, such as large-scale electromagnetic turbulence, when the ions can get energies comparable with experimentally observed ones in the indicated range of L shell values. It is shown that the taking into account electromagnetic fluctuations, accompanying magnetic dipolarization, may explain the appearance of oxygen ion flows with energies greater than 3MeV in the near- Earth’s space.

How to cite: Parkhomenko, E., Kalegaev, V., Malova, H., Panasyuk, M., Popov, V., Vlasova, N., and Zelenyi, L.: Earth’s magnetotail as the reservoir of accelerated single- and multicharged oxygen ions replenishing radiation belts, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-8520, https://doi.org/10.5194/egusphere-egu2020-8520, 2020

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