F-region Dusk Ion Temperature Spikes at the Equatorward Edge of the High Latitude Convection Region

By examining continuous data from the Poker Flat Incoherent Scatter Radar (PFISR) in Poker Flat, Alaska, short-lived enhancements in the F-region ion temperature, or "Tᵢ spikes", were discovered in the evening while the radar was on the equatorward edge of the high latitude convection region. These enhancements were several hundred Kelvin above the background temperature, would last less than 15 minutes and were preceded by sharp depletions in plasma density (of roughly one half). Though they were mostly detected in the summer, 25 events throughout a whole year of data were identi ed in which the spike occurred within 1.5 hours of the density drop. By examining the location of PFISR at the time of the enhancements, as well as the conditions under which these spikes occurred, it was concluded that these enhancements were the result of electric elds increasing the frictional heating between ions and neutrals. By then examining geophysical data, it was found that these events were temporal and related to changes in magnetic indices. One possible explanation for the observations is that the electric eld is at its strongest near the plasmapause during substorms. Another more likely possibility is that during substorms the region of sunward ion convection expands into a region in the evening side where the neutral gas moves in a direction opposite to the ions, thereby enhancing the frictional heating rate.

Name thesis:degree_name

Master of Science (M.Sc.)

Level thesis:degree_level

Masters

Discipline thesis:degree_discipline

Physics

Grantor

University of Saskatchewan

Year dc:date.issued

2013

Author dc:creator

• Goodwin, Lindsay

Advisor dc:contributor.advisor

• St.-Maurice, Jean-Pierre

Committee members dc:contributor.committeemember

• Sofko, George
• Koustov, Sasha
• Smolyakov, Andrei
• Bugg, Jim

• F-region
• Ion Temperature
• Dusk
• High Latitude Convection Region
• Poker Flat Incoherent Scatter Radar
• PFISR
• Frictional heating
• Electric Field

Language dc:language.iso

eng

Handle dc:identifier.uri

https://hdl.handle.net/10388/ETD-2013-12-1333

OAI identifier oai:identifier

oai:harvest.usask.ca:10388/ETD-2013-12-1333