Auroral X ray images

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Abstract
A new X ray ‘pin‐hole’ camera has been developed to study the spatial and temporal characteristics of the energetic component of auroral electron precipitation. The camera obtains spectral information on bremsstrahlung X rays with energies between 22 and 110 keV, and it details spatial structure with scale lengths between 10 and 80 km (9°–62° cone angles). The camera has been deployed by a balloon into several auroral break‐up associated events. In this report preliminary images are shown from these events, and several types of observed phenomena are discussed. These phenomena include the observation of a spectrally soft, 20 km spot which appeared to initiate a major break‐up event and which appeared together with a component which was spectrally hard and spatially uniform. The timing of this event, the multiple components, and the discrepant spatial scales are reminiscent of geostationary observations of dispersionless substorm injections. Also discussed is the slow spatial evolution of X ray burst generating regions, as well as the spatial modulation of precipitation by hydromagnetic oscillation (Pc 5) within the magnetosphere. It appears that small scale spatial structure (≳15 km) is a prominent feature of energetic electron precipitation.