Total Electron Content During Auroral Conditions

• Main Author: Niciejewski, Richard John
• Format: Text
• Language: unknown
• Published: Scholarship@Western 1987
• Subjects: Physics; Atmospheric Science; Churchill
• Online Access: https://ir.lib.uwo.ca/digitizedtheses/1606; https://ir.lib.uwo.ca/context/digitizedtheses/article/2605/viewcontent/NL36055.PDF

Coordinated spectrophotometric and ionospheric electron content measurements were conducted during a variety of auroral conditions at Churchill, Manitoba for a total of 14 clear nights in November and December, 1984. Ground based narrow angle filter photometers measured the temporal history of 4278 and 6300 A emissions for a {dollar}2\sp\circ{dollar} wide, {dollar}100\sp\circ{dollar} long are containing the line of sight path to the polar orbiting HILAT satellite. Optical observations were begun 45 minutes prior to the satellite transit, at one half degree resolution along the long axis of the arc, with an average temporal resolution of seven seconds for each half degree step.;The simultaneous line of sight optical and total electron content measurements indicate that narrow, latitude-limited enhancements of both 4278 and 6300 A radiation, or 6300 A emission only, are associated with total electron content enhancements of the order of {dollar}1 - 2 \times 10\sp{lcub}16{rcub}{dollar} electrons/{dollar}{lcub}\rm m\sp2{rcub}.{dollar} Typical enhancements in 4278 A emission are greater than one kR, while the 6300 A emission is usually enhanced by 500 R above background levels during these events.;A simple, time dependent model of the ionosphere which solves the electron continuity equation as a function of altitude for E and lower F regions is used to calculate electron density height profiles for the approximately vertical, polar geomagnetic field lines that may be traced upwards in the field of view of the photometers. Total electron content obtained by summing across field lines along the line of sight to the HILAT satellite indicate that E region ionization is largely responsible for content variations observed during a "hard" electron precipitation event on DAY353, that both E and F region ionization is required to model content variations during the "medium" precipitation event on DAY351, and that low F region ionization may be partly responsible for content variations during the "soft" event on DAY325. In ...