Structure and dynamics of ionization and auroral luminosity during the auroral events of March 16, 1972, near Chatanika, Alaska

During the period 1000–1030 UT on March 16, 1972, a very dynamic auroral event occurred in the latitudinal region from College to Fort Yukon, Alaska. Simultaneous observations of this auroral event were made with an all‐sky camera, a geomagnetic meridian scanning photometer, an incoherent scatter radar, a three‐component magnetometer, a 30‐MHz riometer, and two VHF/UHF auroral radars. The basic purpose of this report is to illustrate the advantages of such coordinated measurements and the possibilities for future experiments. These preliminary results point out many relationships which, although not hitherto unknown, are important to the understanding of the auroral ionosphere. Paramount among these are (1) intense discrete auroral forms (> 25 kR in 4278 Å) are associated with enhanced E‐layer electron densities near 106 electrons/cm3; (2( the riometer data and the height of maximum Ne from the incoherent scatter radar suggest that few energetic (> 40 kev) particles were precipitating during this event; (3) enhanced regions of VHF backscatter seem to be associated with eastward and westward electrojet current systems but do not spatially correspond to the regions of high Ne or bright auroral forms; and (4) the collective data yield a description which indicates that this period is associated with the Harang discontinuity region of the auroral current systems.