Premium
1D hybrid simulations of planetary ion‐pickup: Energy partition
Author(s) -
Cowee M. M.,
Winske D.,
Russell C. T.,
Strangeway R. J.
Publication year - 2007
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2006gl028285
Subject(s) - ion , population , physics , cyclotron , atomic physics , jovian , pickup , instability , computational physics , astrophysics , mechanics , demography , quantum mechanics , artificial intelligence , sociology , planet , computer science , saturn , image (mathematics)
Ion pickup in planetary environments results in unstable newborn ion populations with sufficient free energy to generate electromagnetic plasma waves. Estimates of the SO 2 + pickup rates near the Jovian moon, Io, based on ion cyclotron wave observations assumed that the newborn pickup ions lose 50% of their energy to wave growth. Using one‐dimensional initial‐value hybrid simulation, we test this assumption and predict that at most ∼25% of the energy of the newborn ion population is lost to wave growth for conditions at Io. This energy is lost over >1400 SO 2 + gyroperiods (∼1 hour), with the majority lost after saturation of the instability. Thus the saturation wave energy is low, at <3% of the newborn ion population's energy. In contrast, newborn ions in cometary environments saturate at substantially higher wave energies (∼30% of the newborn ion population's energy), but do not continue to lose energy afterwards.