Simulating Cometary and Stellar X-ray Emission in the Laboratory Using Microcalorimeters and an Electron Beam Ion Trap

The mixing of atomic and macroscopic processes taking place in non‐terrestrial objects creates complex, dynamic, and intriguing environments. High resolution x‐ray spectra from these sources measured by satellites such as Chandra, XMM‐Newton, and the Solar Maximum Mission provide a means for understanding the physics governing these sources. Laboratory measurements of the atomic processes have proved crucial to the interpretation of these spectra. For example using the LLNL electron beam ion traps EBIT‐I & EBIT‐II a detailed study of the x‐ray spectrum of Fe XVII has been conducted addressing the large ratio predicted by theory compared to observations of considerably smaller values of the relative intensity of the 2p‐3d 1P1 resonant to the 3D1 intercombination line. The difference was often attributed to opacity effects. However, laboratory measurements in the optically thin limit agree with observations demonstrating that the prediction is too large and opacity need not be invoked. The laboratory result...