Experimental Study of Magnetic Reconnection Using Merging Plasmas

利用东京大学的TS-3型机器，采用Z-rheta夹紧型球点形成方案，生产了一对小半径约为15cm的自由边界紧致环面。它们的环形等离子体电流约为30kA，在同一方向上被诱导，以允许等离子体通过强制（驱动）磁重联合并。它们由极向等离子体电流产生的环形磁场是平行的或反平行的，允许我们研究磁重联的三维效应。中心圆柱形导体电流为-20kA （REP区）至120kA（托卡马克区），用于向这些合并环面施加外部环面场。极向等离子体电流和外环向磁场电流的变化使得合并等离子体的磁结构发生变化，使得重联角从20个（托卡马克合并）到90个（共螺旋球体合并）再到180个（反螺旋球体合并）连续变化。随着重联角的增大，熔合速度和离子加热均增大。

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.