Dense plasma diagnostics by fast proton beams

Coulomb energy losses by 3-MeV protons in a capillary discharge channel are used as a diagnostics tool to measure the plasma density. By combining the proton energy loss data with the electron temperature measurements,we have been able to diagnose the free electron density nfe=6.4×10¹⁹0ex0excm^-3 in a 3.3-eV CH₂ plasma to an accuracy of ±17%. A considerably better accuracy can be expected for higher values of the electron temperature.