Lab-frame geometry for a two-jet merge. The downstream region grows due to the compression-driven heating and the buildup of material in the merged-plasma region. The compression wave itself is represented by the dotted line in the lower half of the figure.
Comparison of the deceleration profiles that yield singly and doubly peaked distribution functions. We describe the left plot of velocity vs. position as a singly peaked distribution since the center of the merge region has a single velocity and temperature and forms a well-defined, “downstream” region. We call the right figure a doubly peaked distribution since there are two distinct populations at all locations.
Schematic showing the positions of the guns and plasma jets, with the chamber axis marked.
Three plasmoids merge at HyperV in this fast end-on image. A 15 cm diameter circular port behind the merge plasma reflects light, making the merge region appear larger and more diffuse.
Comparison of experimental and simulated merge structures. The experimental image is 10 cm across at the plane of the nozzles. The experimental and simulation data show short, sharp structures radiating from the geometric merge point. This is similar to our model's prediction of shocks near the midlines, gradually becoming broad compressions in the edge regions.
Distance scales as functions of jet speed for 89 amu ions, 1.1 m radius chamber, 1.6 cm radius nozzle, merge half-angle, initial density, and 3.2 eV initial temperature. At low jet speeds, re and lem are longer than the L, suggesting well-defined shocks and pairwise jet interactions. At high speeds, the compression waves are broader than re and lem , suggesting multi-jet interactions dominate and the nonlinear compressions are insufficiently sharp to reach the steady-state shock jump conditions. At all plotted jet speeds, : If a well-defined downstream region exists near the merge point, it has a single well-defined distribution function. At all but the lowest speeds, the edge region exhibits a doubly peaked distribution function.
Distance scales as functions of chamber radius for 77 km/s jets, 89 amu ions, 1.6 cm nozzle, merge half-angle, initial density, and 3.2 eV initial temperature. For all chamber radii, : Near the midline, shocks are expected and yield singly peaked distribution functions.
Distance scales as functions of nozzle radius for 77 km/s jets, 89 amu ions, a 1.1 m radius chamber, merge half-angle, initial density, and 3.2 eV initial temperature. For all nozzle radii, : Near the midline of the jets, shocks are expected and will yield singly peaked distribution functions. Smaller nozzles give doubly peaked distribution functions in the edge region.
Distance scales as functions of merge half-angle for 77 km/s jets, 89 amu ions, 1.1 m chamber radius, 1.6 cm nozzle radius, initial density, and 3.2 eV initial temperature. Guns which are closely spaced around the periphery of the tank have a small merge half-angle, and yield well-defined shocks with nearest-neighbor interactions and a single downstream distribution function for the midline and possibly the edge regions. As the merge half-angle is increased, the downstream region shifts to a doubly peaked distribution and the compression wave broadens to the point it is no longer a well-defined shock and begins to involve multiple-jet interactions.
Distance scales as initial density varies for 77 km/s jets, 89 amu ions, a 1.1 m radius chamber radius, a 1.6 cm nozzle radius, merge half-angle, and 3.2 eV initial temperature. The midline plasma gives a singly peaked distribution function at high densities. The more tenuous jets cannot be well-modeled by sharp shocks and nearest-neighbor interactions. The edge region has a doubly peaked distribution function for all examined initial jet densities, but only the densest jets give well-defined shocks and strict nearest-neighbor merging for the edge region.
Bounding estimates for experimental jet-merge conditions.
Bounding estimates for simulation jet-merge conditions.
Subscripts used for stopping lengths L.
Bounding estimates for two potential 50 km/s reactor configurations. For argon, we use M = 40 amu. For xenon, we use 131 amu.
Bounding estimates for two potential 100 km/s reactor configurations.
Bounding estimates for two potential 200 km/s reactor configurations.
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