On the use of IMAGE FUV for estimating the latitude of the open/closed magnetic field line boundary in the ionosphere

Abstract

Abstract.A statistical comparison of the latitude of the open/closed magnetic field line boundary (OCB) as estimated from the three far ultraviolet (FUV) detectors onboard the IMAGE spacecraft (the Wideband Imaging camera, WIC, and the Spectrographic Imagers, SI-12 and SI-13) has been carried out over all magnetic local times. A total of over 400 000 OCB estimations were compared from December 2000 and January and December of [2001][2002]. The modal latitude difference between the FUV OCB proxies from the three detectors is small, <1 • , except in the predawn and evening sectors, where the SI-12 OCB proxy is found to be displaced from both the SI-13 and WIC OCB proxies by up to 2 • poleward in the predawn sector and by up to 2 • equatorward in the evening sector. Comparing the IMAGE FUV OCB proxies with that determined from particle precipitation measurements by the Defense Meteorological Satellites Program (DMSP) also shows systematic differences. The SI-12 OCB proxy is found to be at higher latitude in the predawn sector, in better agreement with the DMSP OCB proxy. The WIC and SI-13 OCB proxies are found to be in better agreement with the DMSP OCB proxy at most other magnetic local times. These systematic offsets may be used to correct FUV OCB proxies to give a more accurate estimate of the OCB latitude.

A superposed epoch investigation of the relation between magnetospheric solar wind driving and substorm dynamics with geosynchronous particle injection signatures

“…The OCB is then assumed to be placed poleward of the center of the most poleward Gaussian fit meeting the fitting criteria by an amount equal to the Gaussian full width at half-maximum (FWHM). Boakes et al [2008] studied the latitudinal difference between the OCB estimated in this manner and that estimated from particle precipitation measurements from the DMSP spacecraft (thought to provide the most direct and precise proxy for the OCB but unable to provide a global proxy owing to its limited spatial resolution). They found systematic offsets between the two methods (see their Figure 5) that are applied to "correct" the WIC OCB estimates.…”

Comparison of the open-closed field line boundary location inferred using IMAGE-FUV SI12 images and EISCAT radar observations

“…Several techniques have been considered, based on observations of the auroral emissions (Blanchard et al, 1995;Wild et al, 2004;Hubert et al, 2006a;Boakes et al, 2008), in situ particle detection (Newell et al, 1991;Blanchard et al, 1997), analysis of radar backscatter from the moving ionospheric plasma (Milan et al 2003, and references therein; Chisham et al, 2005), or a combination of in situ particle measurements and radar backscatter analysis (Chisham et al, 2004). Estimates of the electron temperature were also used by Østgaard et al (2005) and Aikio et al (2006) to determine the location of the polar cap boundary.…”

“…Hubert et al (2006a) used remote sensing of the proton aurora at all MLT sectors using the Spectrographic Imager at 121.8 nm (SI12) of the Far Ultraviolet (FUV) experiment onboard the Imager for Magnetopause to Aurora Global Exploration (IMAGE) satellite (Mende et al, 2000a, b), and estimated the location of the polar cap boundary as well as the flux opening and closure reconnection voltages. Wild et al (2005) and Boakes et al (2008) used remote sensing of Published by Copernicus Publications on behalf of the European Geosciences Union. the electron-dominated auroral emissions, which can be obtained using the Spectrographic Imager at 135.6 nm (SI13) and the Wide Band Imaging Camera (WIC) instruments of the IMAGE-FUV experiment to estimate the location of the polar cap boundary in MLT sectors uncontaminated by the dayglow.…”

Determining the boundaries of the auroral oval from CHAMP field-aligned current signatures – Part 1

“…Based on the energetic spectra measured by the special sensor for precipitating particles on the Defense Meteorological Satellite Program (DMSP), the auroral boundary index (ABI) model is provided to estimate the equatorward boundary of precipitating auroral electrons (Hardy et al, 2008). Boakes et al (2008) and Longden et al (2010) presented methods for an automatic detection of the auroral oval boundaries from the Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) satellite. The resulting 2.…”