Experimental Investigation of Lower-Hybrid Solitons Using a Large-Volume, High-Density Helicon-Plasma Source

1.日本<max>宇宙航空研究开发机构宇宙航空研究所（日本宇宙航空研究开发机构的一个部门）研制了一个大容量螺旋等离子体装置（直径74厘米，长486厘米，B = 2千克）。通过使用大的平面螺旋天线（直径43厘米，4匝），该装置能够产生世界上最大体积的螺旋等离子体，其n_e [大于或等于] 10^<12>cm^<-3>，对于Ar具有1.500 W的中等RF输入功率（对于He [小于或等于]2 kW）。利用该装置，可以通过（1）改变天线附近的磁场配置和（2）改变天线辐射场图案来控制径向密度分布。东海大学研制了另一种专门用于激发大振幅低杂波的螺旋等离子体装置（直径20 cm，长100 cm，B_<max>= 0.6 kG）。该设备利用专门设计的分段多环天线用于等离子体产生和波激发。在ISAS/JAXA，试图通过使用轴向长栅格天线，在预制的低密度通道内沿轴向沿着激发低混合（LH）腔模。腔本征模的激发尚未得到证实.在东海，为了激发LH孤子，已经开始了一系列的实验，使用多环天线的外部部分作为激励器。在未来的实验中，我们将尝试观察与LH孤子相关的局域场对等离子体离子的交叉场加速。

1. A large volume helicon-plasma device (74 cm in diameter, 486 cm in length, and B_<max> = 2 kG) has been developed at ISAS/JAXA (the Institute of Space and Astronautical Science, a division of the Japan Aerospace Exploration Agency). With the use of a large flat-spiral antenna (43 cm in diameter, 4 turns), the device is capable of producing a world-largest-volume helicon-plasma of n_e 【greater than or equal】 10^<12> cm^<-3> with moderate rf input power of 〜500 W for Ar (【less than or equal】2 kW for He).2. With this device, it is possible to control the radial density profile by (1) changing the magnetic-field configuration near the antenna and (2) changing the antenna radiation-field patterns.3. Another helicon-plasma device (20 cm in diameter, 100 cm in length, and B_<max> = 0.6 kG), which is specialized to excite large amplitude lower-hybrid waves, has been developed at Tokai University. The device utilizes a specially designed segmented multi-loop antenna for both plasma production and wave excitation.4. At ISAS/JAXA, it was attempted to excite lower-hybrid (LH) cavity modes inside a pre-produced low density channel along the axis by using an axially long grid-antenna. The excitation of cavity eigen-modes has not been confirmed yet.5. At Tokai, a series of experiments has been initiated in order to excite LH solitons using an outer part of the multi-loop antenna as an exciter.6. In the future experiment, it will be attempted to observe cross-field acceleration of plasma ions due to localized fields associated with LH solitons.