We analyze measurements of bipolar, Debye-scale electrostatic structures and turbulence measured in the transition region of the Earth's collisionless bow shock. In this region, the solar wind electron population is slowed and heated, and we show that this turbulence correlates well in amplitude with the measured electron temperature change. The observed bipolar structures are highly oblate and longitudinally polarized and may instantaneously carry up to 10% of the plasma energy ψ ≡ eφ/kbTe ≈ 0.1 before dissipating. The relationship between ψ and the field-aligned scale size Δ∥ of the Gaussian potential suggests that the bipolar structures are BGK trapped particle equilibria or electron hole modes. We suggest a generation scenario and a potential role in dissipation.
Bibliographical noteFunding Information:
Work on the Wind spacecraft is supported at University of California at Berkeley by NASA grants NAG5-2815 and NAG5-7691 to the University of California.
- Shock waves