Self-consistent evolution of auroral downward-current region ion outflow and moving double layer

• Published in: Geophysical research letters Vol. 36; no. 21; pp. np - n/a
• Main Authors: Hwang, K.-J., Ergun, R. E., Newman, D. L., Tao, J.-B., Andersson, L.
• Format: Journal Article
• Language: English
• Published: Washington, DC Blackwell Publishing Ltd 01-11-2009; American Geophysical Union; John Wiley & Sons, Inc
• Subjects: Atmospheric sciences; Conics; Control systems; Double layer; Earth sciences; Earth, ocean, space; Evolution; Exact sciences and technology; Geophysics; Heating; ion outflow; ion perpendicular heating; Ions; Magnetism; Outflow; Simulation; models; simulation; focus; Intensification; electrons; in situ; Ion heating; currents; Feedback; warming; ions; reduction; Phase space; populations; Double layers
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2009GL040585

Vlasov simulations have been performed to investigate the development and evolution of the parallel potential drop, often structured as a localized double layer (DL), electron phase‐space holes, and ion perpendicular heating, resulting in ion outflow in the auroral downward‐current region. We focus on the feedback between a moving DL and heated ions, suggesting a self‐consistent model: the heated ions regulate the evolution of the DL which controls the level of ion heating and, consequently, the outflow rate. Strongly heated ions forming conics are found in agreement with in‐situ observations. The intensification and widening of the DL develops with time, and the DL eventually weakens due to a reduction in the background population resulting from excessive ion heating.