Testing electric field models using ring current ion energy spectra from the Equator-S ion composition (ESIC) instrument

L. M. Kistler (1) , B. Klecker (2) , V. K. Jordanova (1) , E. Möbius (1) , M. A. Popecki (1) , D. Patel (1) , J. A. Sauvaud (3) , H. Rème (3) , A. M. Di Lellis (4) , A. Korth (5) , M. Mccarthy (6) , R. Cerulli (4) , M. B. Bavassano Cattaneo (4) , L. Eliasson (7) , C. W. Carlson (8) , G. K. Parks (6) , G. Paschmann (2) , W. Baumjohann (2) , G. Haerendel (2)

1 SSC - UNH Space Science Center [Durham]
2 MPE - Max-Planck-Institut für Extraterrestrische Physik
3 CESR - Centre d'étude spatiale des rayonnements
4 IFSI - Istituto di Fisica dello Spazio Interplanetario
5 MPI Aeronomie - Max-Planck-Institut für Aeronomie
6 University of Washington [Seattle]
7 IRF - Swedish Institute of Space Physics [Kiruna]
8 University of California

During the main and early recovery phase of a geomagnetic storm on February 18, 1998, the Equator-S ion composition instrument (ESIC) observed spectral features which typically represent the differences in loss along the drift path in the energy range (5–15 keV/e) where the drift changes from being E × B dominated to being gradient and curvature drift dominated. We compare the expected energy spectra modeled using a Volland-Stern electric field and a Weimer electric field, assuming charge exchange along the drift path, with the observed energy spectra for H⁺ and O⁺. We find that using the Weimer electric field gives much better agreement with the spectral features, and with the observed losses. Neither model, however, accurately predicts the energies of the observed minima.

Domaines: Océan, Atmosphère; Sciences de la Terre

L. M. Kistler, B. Klecker, V. K. Jordanova, E. Möbius, M. A. Popecki, et al.. Testing electric field models using ring current ion energy spectra from the Equator-S ion composition (ESIC) instrument. Annales Geophysicae, 1999, 17 (12), pp.1611-1621. ⟨hal-00329150⟩