Precision electron flow measurements in a disk transmission line

There have been several models which have been successful in characterizing many aspects of the electron flow in simple self-insulated geometries. For complicated structures, which are typically found in actual systems, particle-in-cell (PIC) calculations are used. These simulation models have demonstrated a fundamental difficulty in resolving the electron flow in strongly insulated systems. When the electron flow is confined to a very small sheath size, relative to the transmission line gap, finer meshing must be applied near the cathode surface. This increase in cells can lead to inadequate resolution through a process known as "numerical heating". Precise measurements of these electron flows, typically found in low-impedance driven loads, are essential in providing a benchmark for these widely used simulation techniques. Detailed measurements conducted on a low-impedance disk transmission line provide a useful comparison between the theoretical models and the simulation results. In addition a method for directly measuring the electron current at the load of a strongly insulated system is developed. This would circumvent the difficulty of typical diagnostic methods in resolving these electron flows which are usually minimized for optimal efficiency.