Solar System Frontier - Exploring the Heliospheric Interface from 1 AU
M. Gruntman (2006), JBIS, 59, 54-58Refcode
: Heliosphere, heliopause, interstellar medium, ENA, EUVAbstract:
The region where the expanding solar wind meets the surrounding galactic medium remains poorly explored. The structure of and the physical processes at this solar system frontier - the heliospheric interface - are of fundamental importance for understanding the interaction of our star, the Sun, with the galactic medium. This region also needs to be charted for optimizing our first foray into interstellar space by the Interstellar Probe mission and for supporting the truly interstellar exploration of the future. The present concepts of the heliospheric interface are based on scarce and mostly indirect experimental data and limited by the technical difficulties and budgetary realities of sending space probes to this distant region. In addition, the sheer size of the essentially asymmetric heliosphere calls for remote techniques to probe its global three-dimensional properties. We describe two experimental approaches for probing the solar system frontier from 1 AU. Imaging in fluxes of energetic neutral atoms (ENAs) will determine the nature of the termination shock and the properties of the solar plasma in the heliospheric sheath. Then, imaging of the heliosphere in extreme ultraviolet (EUV) will map the heliopause. NASA recently selected a new dedicated space mission to image the heliosphere in ENA fluxes. The efforts in EUV mapping of the heliopause presently focus on development of the mission concept and enabling instrumentation.
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