SCIFER - HEIGHT MEASUREMENTS OF THE MIDMORNING AURORA

Dual-site ground-based optical observations were performed January 25, 1995 in support of the SCIFER rocket campaign (Sounding of the Cleft lon Foundation Energization Region). Two Meridan Scanning Photometers (MSPs) were operative simultaneously at Ny-Alesund (NYA) and Nordlysst asjonen in Adventdalen (LYR) 118 km apart in the geomagnetic meridian. The photometers at each station scanned approximately along the same geomagnetic meridian plane and measured the intensity of auroral wavel engths as a function of zenith angle and time. The principal wavelengt hs used in the present analysis were the green 5577 A and the red 6300 Angstrom emission lines of atomic oxygen. For the magnetospheric clef t auroral activity studied here at 10 hr magnetic local time (MLT), th e luminosity maximum for the green line varied in altitude between 125 and 160 km. The red line maximum was in the range 200 to 220 km. The absolute intensity ratio and the height-luminosity profiles obtained u sing this method were consistent with the near simultaneous rocket mea surement of the field-aligned electrons having a characteristic energy of 230 eV by the SCIFER experiment [Lorentzen, et al., 1996]. Geomagn etic disturbance data obtained during the flight included an example o f a magnetic Impulse event (MIE) coinciding with a bright, discrete ar c. The altitude of this are was > 140 km, and it is doubtful that it p roduced an increase of conductivity in the E Region or developed a cur rent system which could be associated with the MIE. lt is proposed tha t the transient magnetic events were associated with the energetic pul sating aurora which was occurring equatorward of the zenith. In additi on, the altitude of three poleward-moving auroral forms (PMAFs) was me asured, Within the error of the observations, the PMAF's do not seem t o change in altitude with increasing latitude. The sample is too small for a definitive conclusion, but the method shows promise.