抄録
ホイッスラー波の伝播を研究するために磁化プラズマ装置を製作し,プラズマ諸量の測定を行った.チェンバーは内径45 cm,長さ230 cmで8個のコイルにより最大400ガウスの磁場が印加できる.プラズマは,直径21 cm の酸化膜陰極とその前に置かれたグリッドまたは陽極との個のパルス放電により生成する.パルス幅4 msec,くり返し4Hzで最大放電電圧110 V,電流350 Aである.放電はアルゴンガス中(ガス圧5×10^<-5>〜5×10^<-4> Torr)で行い,電子密度≲10^<12> cm^<-3>,電子温度=1〜4eVのプラズマが得られている.ホイッスラー波の伝播実験はアフターグロープラズマ(電子温度≃0.1eV)中でも行い分散関係を測定した.不均一プラズマ中に小さいアンテナでホイッスラー波を励起し,等位相線と振幅の分布を測定した.位相速度と群速度の方向を理論と比較している.
A magnetized plasma device which is suitable to experiments on whistler wave propagations has been produced and tested. The chamber is 45 cm in inner diameter and 230 cm in length. Magnetic field of up to 400G can be applied along the chamber. A plasma is produced by a pulsed discharge between an oxide-coated cathode of 21 cm diameter and a grid or an anode. The width and the repetition of the pulse are 4msec and 4 Hz, respectively. A maximum discharge voltage is 110V and a current is 350A. The discharge is made in argon gas of pressure 5 × 10^<-5> 〜 5 × 10^<-4> Torr. The density and the temperature of electrons are ≲ 10^<12> cm^<-3> and 1 〜 4 eV, respectively. Propagation of whistler wave is studied also in an after glow plasma (the electron temperature 〜0.1 eV) and dispersion relations are measured for some different plasma parameters. Equi-phase contours and amplitude profiles of whistler waves which are excited by a small antenna and which propagate in a non-uniform plasma are measured along and across the magnetic field. Directions of group and phase velocities with respect to the magnetic field are obtained and compared with a theory.
