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This paper describes the behavior of plasma parameters in the E-divertor region of GAMMA 10/PDX numerically by using the multi-fluid code (LINDA) during injection of hydrogen (H) and Argon (Ar). A remarkable reduction in the electron temperature (T e) has been recognized due to Ar injection. For only Ar 6.0 × 10 17 m −3 injection, T e on the target plate decreases to nearly 10 eV. T e also reduces according to the increment of H injection. The ion temperature (T i) on the target plate also decreases according to the increment of injected H neutral density. A tendency of saturation in the particle flux and the electron density is observed at the higher H injection in the case of simultaneous injection of H and Ar. The charge exchange loss enhances significantly during H injection. The radiation power loss also enhances for Ar injection.

This paper investigates the impact of Krypton (Kr) seeding on plasma parameters in the D-module of GAMMA 10/PDX experimentally based on the calorimeter, Langmuir probe and high-speed camera measurements. The heat flux distribution along the V-shaped target plate reduces with the increasing Kr injection. The time behavior of ion flux shows that it decreases with the increase of Kr seeding. The electron temperature (T e ) reduces significantly due to Kr seeding into the D-module. The electron density shows a so-called roll-over phenomenon during Kr seeding. The heat and ion fluxes reduce with the increasing Kr seeding into the D-module. Two-dimensional images captured by the high-speed camera also show that the emission intensity significantly reduces inside the V-shaped target at the higher Kr injection. These outcomes represent the impact of Kr seeding for generating the detached plasma.

Sensitivity of the ASDEX type fast ionization gauge (AIG) to several species of gases; hydrogen, nitrogen, noble gases and their mixtures have been investigated. Mixtures of hydrogen-helium and hydrogen-argon with total gas pressure from 0.2 Pa to 1.5 Pa are investigated in order to simulate the environment of divertor regions. It has been found that the observed output current of AIG in mixed gases are larger than the theoretical output current evaluated from the partial pressures and the sensitivities for pure gases. The enhancement of the AIG sensitivity observed in mixed gas conditions suggests that the ionization is enhanced due to the mixing of different gases. A qualitative analysis on the ionization reactions and their cross-sections has indicated that ionization related with metastable atoms of helium or argon is causing the changes in AIG sensitivity.

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