Characteristics of collisional damping of surface ion-acoustic mode in Divertor Plasma Simulator-2 (DiPS-2)

Abstract

and (3) the collisional damping dominates for the large parallel wavenumber, and the decay constant is given as γ ≈ −νin/16, where νin is the ion–neutral collisional frequency. An experimental simulation of the above theoretical prediction has been done in the argon plasma of DiPS-2, which has the following parameters: plasma density ne = (2–9) × 1011 cm−3, Te = 3.7 − 3.8 eV, Ti = 0.2 − 0.3 eV and collision frequency νin = 23 − 127 kHz. Although the wavelength should be specified with the given parameters of DiPS-2, the collisional damping is found to be γ = (−0.9 to − 5) × 104 rad s−1 for k λDe = 10, while the Landau damping is found to be γ = (−4 to − 9) × 104 rad s−1 for k λDe = 0.1.