Controlling Electrostatic Charge on Particles Moving on a Dielectric Plate by Charge Extraction using an Atmospheric Pressure Plasma Jet

大気圧プラズマジェットから生成される電荷を用いて，連続供給される粒子を誘電板上で帯電させる実験を行った．1 SLM（標準状態1 L/min）のヘリウムガスを供給し，6 kHz, 5 kVの交流電圧に−5 kVから+5 kVの直流バイアス電圧を加えて大気圧プラズマジェットを生成した．直流バイアス電圧の変更によって，プラズマ中から正あるいは負の電荷を任意の割合で抽出し，誘電板の表面に均一に付与した．誘電板上の表面電荷密度は，表面電位で評価した．傾斜した誘電板上で粒子を移動させると，粒子は誘電板上の電荷に応じて帯電した．粒子の帯電は，粒子の初期電荷に依存するが，誘電板の材質や外部電場の影響を受けないことがわかった． / Experiments were carried out on the electric charging of particles continuously fed on a dielectric plate using charges generated by an atmospheric pressure plasma jet. The jet was generated by supplying 1 SLM (standard liter per minute) of helium gas and by applying AC voltage (6 kHz, 5 kV) and DC bias voltage (range: -5 to +5 kV). By varying the DC bias voltage, positive or negative charges could be extracted at a certain ratio from the plasma; the charges were homogeneously deposited onto the dielectric plate. The surface charge density of the dielectric plate was evaluated using surface potential. When the particles moved on the inclined dielectric plate, the particles were charged according to the amount of charge on the dielectric plate. It was found that the material of the dielectric plate and the external electric field do not affect the particle charging, although the initial charge does