Abstract
Laboratory measurements of the interaction of low-energy, bare, and hydrogen-like ions with neutral gases are presented. The measurements demonstrate that charge-exchange-induced cometary K-shell X-ray spectra represent rich spectral diagnostics for determining the speed of the solar wind and the collision dynamics within the coma. We show that the K-shell spectrum observed from low-energy ion-neutral collisions (≤ 50 km s-1) has a distinct high-energy component that is suppressed in high-energy collisions (≥800 km s-1). As a result, the hardness ratio of the K-shell spectrum increases by as much as a factor of 4 as the ions decelerate in the coma. The change in spectral shape can be observed even with low-resolution energy dispersive solid-state detectors, opening the possibility of spatial imaging of the solar wind heavy-ion velocity profile in the coma. Our results clearly show that energy-dependent data are needed to fully describe charge-exchange-induced X-ray production in the heliosphere.
Recommended Citation
P. Beiersdorfer et al., "X-ray Velocimetry of Solar Wind Ion Impact on Comets," Astrophysical Journal, vol. 549, no. 1 PART 2, American Astronomical Society; IOP Publishing, Mar 2001.
The definitive version is available at https://doi.org/10.1086/319143
Department(s)
Physics
Keywords and Phrases
Atomic data; Atomic processes; Comets: General; X-rays: General
International Standard Serial Number (ISSN)
1538-4357; 0004-637X
Document Type
Article - Journal
Document Version
Final Version
File Type
text
Language(s)
English
Rights
© 2024 The Authors, All rights reserved.
Creative Commons Licensing
This work is licensed under a Creative Commons Attribution 4.0 License.
Publication Date
01 Mar 2001
Comments
U.S. Department of Energy, Grant NAG-6155