HR: 08:55h
AN: SM51D-04    [Abstracts]
TI: Ion Acceleration in Vlasov Simulations of Double Layers, Electron Holes, and Associated Waves in Earth's Auroral Ionosphere
AU: Sen, N
EM: Naresh.Sen@colorado.edu
AF: University of Colorado, Center for Integrated Plasma Studies, 390UCB, Boulder, CO 80309-0390, United States
AU: * Newman, D L
EM: David.Newman@colorado.edu
AF: University of Colorado, Center for Integrated Plasma Studies, 390UCB, Boulder, CO 80309-0390, United States
AU: Goldman, M V
EM: goldman@spot.colorado.edu
AF: University of Colorado, Center for Integrated Plasma Studies, 390UCB, Boulder, CO 80309-0390, United States
AU: Andersson, L
EM: laila.andersson@lasp.colorado.edu
AF: University of Colorado, Laboratory for Atmospheric and Space Physics, 1234 Innovation Drive, Boulder, CO 80303-7814, United States
AU: Ergun, R E
EM: ree@lasp.colorado.edu
AF: University of Colorado, Laboratory for Atmospheric and Space Physics, 1234 Innovation Drive, Boulder, CO 80303-7814, United States
AB: The localized unipolar electric field of strong double layers (DLs), such as those observed¹ by FAST in the downward current region of the auroral ionosphere, can produce significant acceleration of anti-earthward electrons and earthward ions. However, DLs can also contribute to the energization of ion perpendicular to the geomagnetic field through several different processes: If the DL itself develops structure perpendicular to \mathbf{B}₀, strong local ion heating can result. On the high-potential (high-altitude) side of the DL, electron holes (nonlinear structures with bipolar electric fields resulting from the saturation of a DL-driven electron two-stream instability) can also contribute to the acceleration of ions \perp to \mathbf{B}₀. Finally, oblique wave modes with E_\perp\gg E_\parallel (e.g., lower-hybrid and ion-Bernstein waves) can contribute to perpendicular ion heating both above and below the DL. Two-dimensional Vlasov simulations are employed to study the interactions of DLs, holes, and oblique waves, together with their contributions to perpendicular ion heating rates. Fully kinetic algorithms for unmagnetized ions as well as reduced² algorithms for magnetized ions, are used in this study. ^*Research supported by NASA, NSF, and DOE ¹ R.~E.~Ergun, et al., Phys.~Rev.~Lett., 87, 045003 (2001). ² D.~L.~Newman, et al., Phys.~Plasmas, 14, 055907 (2007).
DE: 7815 Electrostatic structures
DE: 7839 Nonlinear phenomena (4400, 6944)
DE: 7845 Particle acceleration
DE: 7867 Wave/particle interactions (2483, 6984)
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Fall Meeting