(a) Overall objectives and strategy of the proposed work: We propose an investigation of the aurora borealis using X-ray pinhole cameras flown on sounding rockets and narrow-field low-light video cameras on the ground. The experimental objective is to image the X-ray aurora at lower X-ray energies and with better time resolution than that provided by available balloon instruments and at higher X-ray energies and with better spatial resolution than available satellite instruments. The scientific objectives are to develop a more detailed understanding of the spatial structure of the aurora at these energies and to compare the spatial structure of the X-ray aurora with the spatial structure of the visible aurora. The physics responsible for producing the small-scale shape of the X-ray aurora is not understood. The mechanisms that accelerate and precipitate the electrons that produce the X-ray aurora are not understood.
(b) New Task
(c) Description and Plan of Activites: We have developed and flight tested an X-ray pinhole scintillation camera and a sounding rocket borne, parachute deployed payload. Position and energy sensitive detection of individual photon events in the scintillation crystal is accomplished by means of a photon counting image tube. The operating altitude range will be from 80-25 km. The instruments are sensitive to 5-500 keV X-rays and have an angular resolution of 7.9. The first test flight of this camera was in March, 1990 from Poker Flat Research Range. The second test flight of the camera took place in March 1994, at which time the payload was lost. The proposed work includes redesigning the camera and payloads to incorporate state-of-the-art technology, rebuilding two payloads, conducting another campaign to launch two more flights in February, 1997 and analysis of data from these flights and the most recent test flight.
(d) Relevance of Proposed Research to NASA's Space Physics programs: The scientific questions that we propose to study are of fundamental importance in understanding energetic particle precipitation from the magnetosphere and the processes of particle energization that occur during magnetospheric substorms. These questions form part of the central scientific objectives of several programs, including FAST, SAMPEX, and POLAR. We will also complement and extend the work of the X ray imaging experiment on UARS.
(e) Recent related publications include
``Longitudinal differences in electron precipitation near L=4," E. A. Bering III, J. R. Benbrook, H. Leverenz, J. L. Roeder, E. G. Stansbery, and W. R. Sheldon, J. Geophys. Res., 93, 11385-11403 [1988] and ``Imaging of energetic auroral X-rays by a rocket-borne parachuted payload,'' J. R. Benbrook, E. A. Bering, III, H. C. Stenbaek-Nielsen, and T. J. Hallinan, XXI General Assembly of the International Union of Geodesy and Geophysics, Abstracts, A, 146, [1995].