STUDIES OF X-RAY PRODUCTION FOLLOWING CHARGE EXCHANGE RECOMBINATION BETWEEN HIGHLY CHARGED IONS AND NEUTRAL ATOMS AND MOLECULES

We have used microcalorimeters built by the NASA/Goddard Space Flight Center and the Lawrence Livermore National Laboratory SuperEBIT electron beam ion trap to measure X-ray emission produced by charge exchange reactions between highly charged ions colliding with neutral helium, hydrogen, and nitrogen gas. Our measurements show the spectral dependence on neutral species and also show the distinct differences between spectra produced by charge exchange reactions and those produced by direct electron-impact excitation. These results are part of an ongoing experimental investigation at the LLNL SuperEBIT facility of charge exchange spectral signatures and can be used to interpret X-ray spectra produced by a variety of laboratory and celestial sources including cometary and planetary atmospheres, the Earth's magnetosheath, the heliosphere, and tokamaks.