Dust Effects on a Free Presheaths in Weakly Magnetized Plasmas

Dust effects on a diffusion coefficient and a connection length at a free presheath regions have been investigated as a part of experimental simulation of dust interaction with plasmas and plasma edge transport at Divertor Plasma Simulator -- 2 (DiPS-2) with the following conditions: plasma density 1\textasciitilde 10 × 10$^{\mathrm{12}}$ cm$^{\mathrm{3}}$, electron temperature 1 \textasciitilde 10 eV and magnetic field \textasciitilde 1 kG, where the characteristics of DiPS-2 is the following: 12 V and 280 A for LaB$_{\mathrm{6}}$ heating, 50 -- 100 V and 20 -- 40 A for plasma discharge. Pulsed laser beams by a 250 mJ Nd:YAG laser were injected to a tungsten target for production of dust particles. Free presheaths were artificially generated by inserting a tungsten perturbing object with diameter $=$ 1.5 cm at the center of plasmas in DiPS-2. Radial plasma profiles were measured by using a fast scanning probe (FSP) system with triple probe (TP) and Mach probe (MP) and a laser induced fluorescence (LIF) system. Dust effects on a diffusion coefficient and a connection length in the presheath region were analysed by comparing the plasma parameter of dusty and pure plasmas.