We have used a quartz tube 10.8 cm long, 2.8 cm in internal diameter and 1 mm in wall thickness and produced the pinch effect by current in an axial direction in pre-ionized plasma. Before the gas was ionized, a magnetic field in the axial direction was produced by external coils. The following magnitudes are typical: duration of pulse, 25 mμsec; potential difference between the electrodes, 20 kV; current through the tube, 30 kA; gas pressure before ionization 50 mtorr. Measurements were made of the potential difference between the electrodes, the current through the tube and the magnetic field within the tube in both the θ and z directions. It was found that the current skin thickness (3—4 mm) was much larger than any existing theory predicts. A theory based on the assumption that the drift velocity of the electrons is limited by "streaming" instabilities is developed. This theory explains most although not all of the experimental results.
我々は、長さ10.8cm、内径2.8cm、肉厚1mmの石英管を使用し、予備電離されたプラズマ中に軸方向の電流を流すことによってピンチ効果を発生させた。ガスが電離される前に、外部コイルによって軸方向の磁場を生成した。典型的な値は以下の通りである：パルス持続時間25mμ秒、電極間電位差20kV、管内電流30kA、電離前のガス圧50mtorr。電極間の電位差、管内電流、および管内の磁場（θ方向およびz方向の両方）の測定を行った。電流の表皮深さ（3〜4mm）は、既存の理論が予測する値よりもはるかに大きいことが判明した。電子のドリフト速度が「ストリーミング」不安定性によって制限されるという仮定に基づく理論を展開した。この理論は、実験結果のすべてではないが大部分を説明する。