Experimental Study of Magnetic Reconnection Using Merging Plasmas

本文用东京大学的TS-3机器，采用Z-rheta箍缩型球马克成形方案，制造了一对小半径约15 cm的自由边界紧凑环。它们的环形等离子体电流约为30 kA，在相同的方向上感应，以允许等离子体通过强制（驱动）磁重联合并。它们的极向等离子体电流产生的环形磁场是平行或反平行的，使我们能够研究磁场重联的三维效应。中心圆柱导体的电流为-20kA（REP区）至120 kA（托卡马克区），用于向这些合并环施加外环向场。极向等离子体电流和外部环向场电流的变化允许合并等离子体的磁结构发生变化，使得重联角从约20 °（托卡马克合并）到90 °（共螺旋球马克合并）再到180 °（反螺旋球马克合并）连续变化。结果表明，随着重联角的增大，离子的合并速度和加热都增大。

The TS-3 machine at the Univ.Tokyo with the Z-rheta pinch type spheromak formation scheme has been used to produce a pair of free boundary compact toroids with a minor radius of about 15cm. Their toroidal plasma currents of about 30kA,are induced in the same direction to permit the plasmas to merge through forced (driven) magnetic reconnection. Their toroidal magnetic fields produced by the poloidal plasma currents are made either parallel or anti-parallel, permitting us to investigate the three dimensional effects of the magnetic reconnection. A center cylindrical conductor with a current of -20kA (REP region) to 120kA (tokamak region) is used to apply an external toroidal field to these merging toroids. The variation of both poloidal plasma currents and external toroidal field currents permits the change in magnetic configuration of merging plasmas, enabling the reconnection angle to vary continuously from about 20ﾟ (tokamak merging) through 90ﾟ (cohelicity spheromak merging) to 180ﾟ (counter-helicity spheromak merging). It is found that both merging speed and ion heating enlarged with increasing reconnection angle.