CALIBRATED RADIANCE MEASUREMENTS WITH AN AIR-FILLED GLOW DISCHARGE TUBE: APPLICATION TO SPRITES IN THE MESOSPHERE

摘要

Quantitative observations of a large air-filled glow discharge tube are used to shed light on the behavior of sprites in the mesosphere. The optical spectrum in the (red) positive column is shown to resemble the spectrum of the sprite body. Experimental estimates of the electrical conductivity of the positive column are reasonably consistent with theoretical estimates for the conductivity of sprites. The relationship between absolute radiance and current density in the tube are used to interpret the current flow in sprites, under the working assumption that laboratory "DC" excitation is appropriate for time-dependent sprite excitation. In general, the current inferred for sprites is modest in comparison to the current of the parent lightning flash.