Space Science Applications Research Articles

On the equilibrium statistical mechanics of isothermal classical self-gravitating matter

The canonical ensemble is investigated for classical self-gravitating matter in a finite containerΛ [d]⊂ℝ d ,d=3 and 2. Starting with modified gravitational interactions (smoothed-out singularity), it is proven by explicit construction that, in thew *-topology, the canonical equilibrium measure converges to a superposition of Dirac measures when the limit of exact Newtonian gravitational interactions between classical point particles is taken. The consequences of this result for more realistic classical systems are evaluated, and the existence of a gravitational phase transition is proven. The results are discussed with view toward applications in astrophysics and space science. Some attention is paid also to the problem of founding thermodynamics by means of statistical mechanics.

OPEN team selected

The Office of Space Science Applications of the National Aeronautics and Space Administration (NASA) has completed the selection of the scientific team that will work on the science definition for the Origins of Plasma in Earth's Neighborhood (OPEN) mission. These scientists will define the instrument packages that will fly aboard the four‐spacecraft mission proposed for later in the decade. The mission, although not currently authorized, is expected to provide detailed information about the sun's energy and its transfer from the solar wind through the earth's magnetosphere down through the ionosphere, according to NASA.

Electrographic Instrumentation For Ultraviolet Imaging And Spectrography

The latest results in the Naval Research Laboratory program of far-ultraviolet electrographic camera development, and application of these cameras to astrophysical and upper-atmospheric investigations, are presented. A new large electrographic Schmidt camera, of 15 cm aperture and f/2 focal ratio, has been successfully used in two sounding rocket flights, one for direct imagery in the 1230-2000 A wavelength range and the second for objective spectrography in the 950-2000 A range, of stars and nebulae in the Cygnus region of the sky. The camera has an 11° field of view and better than 30 arc sec resolution (2 A spectral resolution with 600 line/mm objective grating). A nebular spectrograph, based on a microchannel-intensified electrographic Schmidt camera, was then payload of a June 1979 rocket flight. It covers the 1050-2000 A range, and can reach emission line features as faint as 10 Rayleighs in 60 second ex-posures with 5 A spectral resolution. Electrographic cameras with mesh-based semitransparent photocathodes, capable of observations in the extreme ultraviolet below 1050 A, are being developed for a number of space science applications. A camera with microchannel intensification is the detector in an XUV airglow/auroral spectrograph used in a February 1978 rocket flight, and cameras without microchannel intensification are proposed for various solar XUV spectrographic and spectroheliographic applications.