CALCULATION OF AURORAL BALMER VOLUME EMISSION HEIGHT PROFILES IN THE UPPER-ATMOSPHERE

Energetic protons entering the atmosphere will either travel as aurora l protons or as neutral hydrogen atoms due to charge-exchange and exci tation interactions with atmospheric constituents. Our objective is to develop a simple procedure to evaluate the Balmer excitation rates of H(alpha) and H(beta), and produce the corresponding volume emission r ates vs height, using semi-empirical range relations in air, starting from proton spectra observed from rockets above the main collision reg ion as measured by REASONER el al. [(1968) J. geophys. Res. 73, 4185] and SORAAS et al. [(1974) J. geophys. Res. 79, 1851]. The main assumpt ions are that the geomagnetic field is parallel and vertical, and that the pitch angle of the proton/hydrogen atom is preserved in collision s with atmospheric constituents before being thermalized. Calculations show that the largest energy losses occur in the height interval betw een 100 and 125 km, and the corresponding volume emission rate vs heig ht profiles have maximum values in this height interval. The calculate d volume emission rate height profile of H(beta) compares favorably wi th that measured with a rocket-borne photometer.