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arXiv · 1207.5561

Shocklets, SLAMS, and field-aligned ion beams in the terrestrial foreshock

L. B. Wilson III·A. Koval·D. G. Sibeck·A. Szabo·C. A. Cattell·J. C. Kasper·B. A. Maruca·M. Pulupa·C. S. Salem·M. Wilber
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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). We show that the SLAMS are acting like a local quasi-perpendicular shock reflecting ions to produce the FABs. Previous FAB observations reported the source as the quasi-perpendicular bow shock. The SLAMS exhibit a foot-like magnetic enhancement with a leading magnetosonic whistler train, consistent with previous observations. The FABs are found to have T_b ~ 80-850 eV, V_b/V_sw ~ 1-2, T_{b,perp}/T{b,para} ~ 1-10, and n_b/n_i ~ 0.2-14%. Strong ion and electron heating are observed within the series of shocklets and SLAMS increasing by factors \geq 5 and \geq 3, respectively. Both the core and halo electron components show strong perpendicular heating inside the feature.

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L. B. Wilson III, A. Koval, D. G. Sibeck, A. Szabo, C. A. Cattell, J. C. Kasper, B. A. Maruca, M. Pulupa, C. S. Salem, M. Wilber. 2012-07-23. Shocklets, SLAMS, and field-aligned ion beams in the terrestrial foreshock. https://doi.org/10.1029/2012ja018186

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