[IGPP Everyone] Space Physics Seminar - Friday June 7, 2019 - Last Seminar for the Spring Quarter

[Marjorie Sowmendran]

SPACE PHYSICS SEMINAR

DEPARTMENT OF EARTH, PLANETARY, AND SPACE SCIENCES

DEPARTMENT OF ATMOSPHERIC AND OCEANIC SCIENCES

UNIVERSITY OF CALIFORNIA, LOS ANGELES

(AOS M275C, EPSS M288C)



Statistics and Energetics of Lightning on Venus


Ricky Hart, EPSS UCLA



Abstract

The most recent observations of lightning on Venus come in the form of whistler-mode waves detected by the Venus Express (VEX) mission. The dual fluxgate magnetometer sampled at 128 Hz allowing for detection of signals up to 64 Hz. These signals are found at all local times within the ionosphere, but only near the North Pole because of the spacecraft orbit. The entire 8.5+ year dataset has been analyzed providing 7 hours of whistler activity in total. The majority of the signals were detected when VEX was at ~250 km, approximately 3% of the time at this altitude. Poynting flux calculations are made for every signal detected and analyzed statistically to demonstrate that these waves have a source below the ionosphere. A future mission in a circular orbit that covers lower latitudes would provide an abundance of data allowing for an accurate calculation of the global occurrence rate of lightning and the locations that it is most frequent.



Effects of Solar Wind Parameters on Location of Magnetotail Reconnection

Mark Hubbert, EPSS, UCLA

Abstract

Solar wind dynamic pressure controls the size of the Earth’s magnetosphere. When the dynamic pressure increases, the magnetotail contracts. This contraction moves the closer magnetic reconnection point in the current sheet closer to Earth than during normal dynamic pressure conditions. The locations of the x-line in the current sheet are expected to be associated with stronger magnetotail and ionospheric plasma responses. We compile events when MMS observed reconnection in the current sheet and Wind observed elevated solar wind dynamic pressure on the dayside (propagated to 20 RE upstream). By comparing the locations of tail reconnection events at high solar wind dynamic pressure to those of reconnection events at low solar wind dynamic pressure, we can further understand why substorms can vary in their effects on magnetospheric plasma.



Friday, June 7, 2019

Room 6704 Geology

3:30 - 5:00 PM





Presiding: R. J. Strangeway 
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