Open AccessCharge exchange contribution to the decay of the ring current, measured by energetic neutral atoms (ENAs)
Author(s) -
Jorgensen A. M.,
Henderson M. G.,
Roelof E. C.,
Reeves G. D.,
Spence H. E.
Publication year - 2001
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2000ja000124
Subject(s) - ring current , energetic neutral atom , current (fluid) , atomic physics , phase (matter) , physics , ion , ring (chemistry) , charge exchange , charge (physics) , nuclear physics , plasma , magnetosphere , chemistry , organic chemistry , quantum mechanics , thermodynamics
In this paper we calculate the contribution of charge exchange to the decay of the ring current. Past works have suggested that charge exchange of ring current protons is primarily responsible for the decay of the ring current during the late recovery phase, but there is still much debate about the fast decay of the early recovery phase. We use energetic neutral atom (ENA) measurements from Polar to calculate the total ENA energy escape. To get the total ENA escape we apply a forward modeling technique, and to estimate the total ring current energy escape we use the Dessler‐Parker‐Sckopke relationship. We find that during the late recovery phase of the March 10, 1998 storm ENAs with energies greater than 17.5 keV can account for 75% of the estimated energy loss from the ring current. During the fast recovery the measured ENAs can only account for a small portion of the total energy loss. We also find that the lifetime of the trapped ions is significantly shorter during the fast recovery phase than during the late recovery phase, suggesting that different processes are operating during the two phases.