Ion cyclotron instability at Io: Hybrid simulation results compared to in situ observations

0465320 - ÚFA 2017 RIV US eng J - Článek v odborném periodiku
Šebek, Ondřej - Trávníček, Pavel M. - Walker, R. J. - Hellinger, Petr
Ion cyclotron instability at Io: Hybrid simulation results compared to in situ observations.
Journal of Geophysical Research-Space Physics. Roč. 121, č. 8 (2016), s. 7514-7534. ISSN 2169-9380. E-ISSN 2169-9402
Institucionální podpora: RVO:68378289
Klíčová slova: Io * ionization processes * ion cyclotron waves
Kód oboru RIV: BL - Fyzika plazmatu a výboje v plynech
Impakt faktor: 2.733, rok: 2016
http://onlinelibrary.wiley.com/doi/10.1002/2016JA022477/abstract

We present analysis of global three-dimensional hybrid simulations of Io's interaction with Jovian magnetospheric plasma. We apply a single-species model with simplified neutral-plasma chemistry and downscale Io in order to resolve the ion kinetic scales. We consider charge exchange, electron impact ionization, and photoionization by using variable rates of these processes to investigate their impact. Our results are in a good qualitative agreement with the in situ magnetic field measurements for five Galileo flybys around Io. The hybrid model describes ion kinetics self-consistently. This allows us to assess the distribution of temperature anisotropies around Io and thereby determine the possible triggering mechanism for waves observed near Io. We compare simulated dynamic spectra of magnetic fluctuations with in situ observations made by Galileo. Our results are consistent with both the spatial distribution and local amplitude of magnetic fluctuations found in the observations. Cyclotron waves, triggered probably by the growth of ion cyclotron instability, are observed mainly downstream of Io and on the flanks in regions farther from Io where the ion pickup rate is relatively low. Growth of the ion cyclotron instability is governed mainly by the charge exchange rate.
Trvalý link: http://hdl.handle.net/11104/0263937