Quarterly Report April 1, 1995 - June 30, 1995 Contract No. 9F007-5-8005/01-SR SSC File No. 019SR.9F007-5-8005 Prepared by: David P. Steele Institute of Space and Atmospheric Studies Department of Physics University of Saskatchewan 116 Science Place Saskatoon, SK, CANADA S7N 5E2 Prepared for: Mr. Glen Rumbold Scientific Authority Canadian Space Agency Space Science Program 100 Sussex Drive, Room 1039 Ottawa, ON, CANADA K1A 0R6 Part 1: 1. The project is on schedule. 2. The project is within budget. 3. The project is free of any areas of concern in which the assistance or guidance of Canada may be required. Part 2: Tasks: 1. Faint arc characteristics study 2. Polar mesopause wave spectrum study 3. Search for alternate funding/permanent position 1. Description of progress 1.1 Faint arc characteristics study Work on this task began with the investigation of a previously unreported high-latitude optical emission morphology, as described in the following paragraphs. A statistical study of the characteristics of faint arcs will be undertaken beginning in September 1995, immediately following the submission of a manuscript on the investigation now described. In reviewing the data from the past winter, I noticed more than two dozen occurrences of a phenomenon to which I have assigned the tentative name "polar diffuse aurora." I have begun a study of the phenomenon, using imaging and ionosonde data from Eureka, interplanetary magnetic field (IMF) and solar wind data from the WIND spacecraft, and low-altitude precipitating particle measurements from the USAF Defense Meteorological Satellite Program (DMSP) constellation of spacecraft. From case studies of five occurrences, the following characteristics have been identified: - Faint diffuse emission at 630.0 nm with an approximately sun-aligned boundary is observed to drift into the Polar Camera field of view from either the dusk side or the dawn side (Figure 1); - The emission boundary drifts in the direction of the dawn-dusk component of the IMF; - For most cases, the IMF has a northward component; - The ionosonde data indicate F-region plasma drift in the direction of the optical emission boundary drift, as well as either sunward or antisunward; - DMSP particle data along the dusk-dawn meridian indicate major contraction of the polar cap, and very weak low-energy particle fluxes above the region of enhanced 630.0 nm emission above the airglow background; The following steps are planned, which it is expected will provide a more complete picture of the character of the phenomenon, suitable for publication: - Examination of the remaining occurrences of enhanced diffuse emission during the past winter; - Examination of images at 557.7 nm ([OI]) and 785.0 nm (N2+ Meinel) for evidence of enhanced emission (diffuse or otherwise); - Examination of ionograms from Eureka during occurrences of enhanced diffuse emission to assess the contribution of dissociative recombination to the observed emission; - Determination (by detailed modelling) of the extent to which the measured soft electron fluxes can account for the measured 630.0 nm emission enhancement; - Determination of the location of the enhanced emission with respect to the large scale high latitude convection pattern as measured by instruments on the DMSP satellites; - Examination of ground magnetometer records from Eureka during occurrences of enhanced diffuse emission; - Assessment of the extent of the diffuse emission using images from other high latitude observatories. 1.2 Polar mesopause wave spectrum study Work on this task has been on the provision of a fundamental analysis tool for subtracting images of continuum emission from images of spectral features (such as the R and Q branches of the OH (6-2) band). This tool yields spectrally pure images which can then be used for quantitative investigations (such as inference of OH rotational temperature from the relative brightnesses of the R and Q branches). Application of the tool constitutes the next step in this task. 1.3 Search for additional funding and a permanent position I applied for the Assistant Professorship open in the Institute of Space and Atmospheric Studies at the University of Saskatchewan, but was unsuccessful. 2. Explanation of variation(s) I decided to pursue the investigation of "polar diffuse aurora" before studying faint arc characteristics because of the novelty of the observations. I am unaware of any previous observations of this phenomenon, although imagers of probably sufficient sensitivity have operated in the polar cap for some years now. It appears possible that the phenomenon will provide new information about the topology of the magnetic field near the geomagnetic pole, and about solar wind plasma entry into the magnetosphere for northward IMF. 3. Trips and conferences I made one trip during the period covered by this report. 3.1 University of Western Ontario, May 26-28, 1995 On May 26-28 I was in London, ON. I attended a workshop on polar science hosted by the University of Western Ontario on the 26th, at which all groups doing atmospheric and space science with observations from Eureka were represented. I reported on my investigation of "polar diffuse aurora", and met the key workers in the Institute for Space and Terrestrial Science (ISTS) group making lidar observations at Eureka. On the following morning, Prof. J. MacDougall of U.W.O. (the P.I. of the Canadian Advanced Digital Ionosondes (CADIs) located at Eureka and elsewhere in the Arctic), Prof. D. J. McEwen of the U. of Saskatchewan, and I met to identify opportunities for collaborative work on the observations from the past winter at Eureka. Numerous interesting questions were identified, and initial steps have been taken in addressing some of them. For the remainder of the 27th, and most of the 28th, Prof. MacDougall introduced me to the data acquired by his CADI at Eureka. He provided hard copy of summary plots for the months of December 1994 and January 1995, and a CD-ROM of all CADI data acquired (both at Eureka and other sites) in February 1995, together with software to process and analyze the data. CADI data will play an important role in all of my proposed studies of ionospheric phenomena. U.W.O. covered my travel, and most of my accomodation costs for the dates of the workshop. 4. Major Equipment No major equipment was purchased or constructed during the period covered by this report.