Measurement of ion temperature and density profiles with a time-of-flight type neutral-particle analyzer

High beta plasmas in the anchor cell of the GAMMA 10 tandem mirror are formed by using a fundamental ion cyclotron resonance heating. Because the closed resonance surface exists near the midplane of the anchor cell, strongly peaked profile of the plasma pressure will be formed. To measure the axial profiles of the ion temperature and density, a time-of-flight type neutral-particle analyzer (TOF–NPA) has been developed. TOF–NPA can detect neutral particles and photons separately at the same time. The ion temperature and density have been evaluated from the particle and photon signals, respectively. The peaked profile of the ion temperature within the closed resonance surface has been confirmed