High-Resolution Charge Exchange X-Ray Emission At Solar Wind Velocities

With a high-resolution x-ray quantum microcalorimeter detector, x-ray emissions following single charge exchange are measured for 392 km/s, 554 km/s, 678 km/s, and 876 km/s Ne8+ on He collisions. Line ratios are reported for 3p -> 2s, 4s -> 2p, 3d -> 2p, and 4d -> 2p emissions by normalizing these to 4p -> 2s emission. It is found that the measured line ratios are in good agreement with a multichannel Landau-Zener calculation for the 4s -> 2p emission. However, unlike the calculation, the measured line ratios for 3p -> 2s, 4d -> 2p and 3d -> 2p emissions show an increasing state-selectivity for 4d and 4f states with increasing collision velocity. This probably indicates the importance of rotational coupling effects in high angular momentum population.