Ion energy spectrum in the Texas Tokamak

The Texas Tokamak is a toroidal plasma device designed to study the turbulent heating and confinement of plasma. To determine the ion temperature, the energy distribution of the charge exchange neutrals escaping the plasma was measured. Charge exchange neutrals leaving the plasma through a small port in the vacuum vessel pass through a helium stripping cell where a fraction of them are ionized. The energies of the resulting beam of ions were analyzed in a 1270 electrostatic energy monochrometer. The current from the energy analyzer was collected and amplified with a Daly detector. The resulting energy spectra yielded information about the ion temperature and the fractional population of ions that were heated as a function of tokamak parameters such as total plasma density and the charging voltage of the turbulent heating capacitor bank. This experiment revealed that a fraction of the plasma ions were heated to temperatures of 2000 to 5000 electron volts