Abstract
We present Wind spacecraft observations of ion distributions showing field-aligned beams (FABs) and large-amplitude magnetic fluctuations composed of a series of shocklets and short large-amplitude magnetic structures (SLAMS). The FABs are found to have Tb ∼80 - 850 eV, Vb/V sw ∼1. 3 - 2. 4, T∥,b/Tb ∼1-8, and nb/no ∼0.2-11%. Saturation amplitudes for ion/ion resonant and non-resonant instabilities are too small to explain the observed SLAMS amplitudes. We show two examples where groups of SLAMS can act like a local quasi-perpendicular shock reflecting ions to produce the FABs, a scenario distinct from the more common production at the quasi-perpendicular bow shock. The SLAMS exhibit a foot-like magnetic enhancement with a leading magnetosonic whistler train, consistent with previous observations. Strong ion and electron heating are observed within the series of shocklets and SLAMS with temperatures increasing by factors ≠5 and ≠3, respectively. Both the core and halo electron components show strong perpendicular heating inside the feature. Key Points Field-aligned ion beams produced locally by SLAMS SLAMS cause strong anisotropic ion and electron heating SLAMS can act like local quasi-perpendicular shocks
Original language | English (US) |
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Pages (from-to) | 957-966 |
Number of pages | 10 |
Journal | Journal of Geophysical Research: Space Physics |
Volume | 118 |
Issue number | 3 |
DOIs | |
State | Published - 2013 |
Keywords
- SLAMS
- field-aligned ion beams
- particle acceleration
- particle reflection
- wave-particle interaction
- whistler mode waves