X rays from solar wind charge exchange at Mars: A comparison of simulations and observations

Geophysical Research Letters (Impact Factor: 3.98). 01/2004; 31(22). DOI: 10.1029/2004GL020953

ABSTRACT A hybrid simulation of the solar wind-Mars interaction and a test particle simulation of heavy ion trajectories near Mars are used to compute the contribution from solar wind charge exchange processes to the X-ray emission from Mars. It is found that the X-ray halo observed by the Chandra X-ray observatory can be explained by emissions from heavy, highly charged, ions in the solar wind undergoing charge exchange collisions in the upper atmosphere of Mars.

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    ABSTRACT: The objective of the Diffuse X-ray emission from the Local Galaxy (DXL) sounding rocket experiment is to distinguish the soft X-ray emission due to the Local Hot Bubble (LHB) from that produced via Solar Wind charge exchange (SWCX). Enhanced interplanetary helium density in the helium focusing cone provides a spatial variation to the SWCX that can be identified by scanning through the focusing cone using an X-ray instrument with a large grasp. DXL consists of two large proportional counters refurbished from the Aerobee payload used during the Wisconsin All Sky Survey. The counters utilize P-10 fill gas and are covered by a thin Formvar window (with Cyasorb UV-24 additive) supported on a nickel mesh. DXL's large grasp is 10 cm2 sr for both the 1/4 and 3/4 keV bands. DXL was successfully launched from White Sands Missile Range, New Mexico on December 12, 2012 using a Terrier Mk70 Black Brant IX sounding rocket. The Sheath Transport Observer for the Redistribution of Mass (STORM) instrument is a prototype soft X-ray camera also successfully own on the DXL sounding rocket. STORM uses newly developed slumped micropore (`lobster eye') optics to focus X-rays onto a position sensitive, chevron configuration, microchannel plate detector. The slumped micropore optics have a 75 cm curvature radius and a polyimide/aluminum filter bonded to its surface. STORM's large field-of-view makes it ideal for imaging SWCX with exospheric hydrogen for future missions. STORM represents the first flight of lobster-eye optics in space.
    Proc SPIE 09/2013;
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    ABSTRACT: Aims. We study the soft X-ray emission induced by charge exchange (CX) collisions between solar-wind, highly charged ions and neutral atoms of the Martian exosphere. Methods. A 3D multi species hybrid simulation model with improved spatial resolution (130 km) is used to describe the interaction between the solar wind and the Martian neutrals. We calculated velocity and density distributions of the solar wind plasma in the Martian environment with realistic planetary ions description, using spherically symmetric exospheric H and O profiles. Following that, a 3D test-particle model was developed to compute the X-ray emission produced by CX collisions between neutrals and solar wind minor ions. The model results are compared to XMM-Newton observations of Mars. Results. We calculate projected X-ray emission maps for the XMM-Newton observing conditions and demonstrate how the X-ray emission reflects the Martian electromagnetic structure in accordance with the observed X-ray images. Our maps confirm that X-ray images are a powerful tool for the study of solar wind - planetary interfaces. However, the simulation results reveal several quantitative discrepancies compared to the observations. Typical solar wind and neutral coronae conditions corresponding to the 2003 observation period of Mars cannot reproduce the high luminosity or the corresponding very extended halo observed with XMM-Newton. Potential explanations of these discrepancies are discussed.
    Astronomy and Astrophysics 09/2012; · 5.08 Impact Factor
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    ABSTRACT: We report charge exchange cross sections for the collision system C5 + + H using the quantum mechanical molecular-orbital close-coupling method. The multi-reference single- and double-excitation configuration interaction method is used to produce potential and coupling data, and scattering calculations are performed for collision energies between 0.01 eV/u to 1 keV/u for all l,S-resolved states within the n = 3 and 4 manifolds. The n = 5 manifold is represented through the inclusion of the 5s state. To predict cross sections at higher energies, we include new results from atomic-orbital close-coupling and classical trajectory Monte Carlo calculations. We briefly discuss applications to x-ray emission within the solar system.
    Journal of Physics B Atomic Molecular and Optical Physics 12/2012; 45(24):245202. · 2.03 Impact Factor

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