Helicon wave excitation with rotating antenna fields
Helicon wave excitation with rotating antenna fields
复制标题
旋转天线场的螺旋波激励
DOI：
10.1088/0963-0252/7/1/009
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发表时间：
1998
影响因子：
3.8
通讯作者：
Francis F. Chen
中科院分区：
文献类型：
--
作者：
D. Miljak;Francis F. Chen
通过使用相控双线天线，通过施加在空间或时间上或同时在空间和时间上旋转的场来激发螺旋波。使旋转方向有利于m=+1或m=-1波，其中m是方位模数，并且m是直接测量的。时间旋转被发现比空间旋转更有效，这使得直接比较激发成为可能。M=-1结构只出现在天线近场，而m=+1模则远向下游传播。高达2千瓦的射频功率、密度分布和天线负载测量表明，m<；0(左手)波耦合很差，m=+1(右手)波是产生良好等离子体所必需的。加载结果表明，天线还耦合到与螺旋波无关的吸收机制。
By using phased bifilar antennas, helicon waves have been excited by applying fields which rotate either in space or in time, or both simultaneously. The direction of rotation is made to favour either m=+1 or m=-1 waves, where m is the azimuthal mode number, and m is measured directly. Rotation in time is found to be more effective than rotation in space and makes possible a direct comparison of excitation. An m=-1 structure was seen only in the antenna near field, while m=+1 modes propagate far downstream. Up to 2 kW of RF power, density profiles and antenna loading measurements show that m<0 (left-hand) waves are poorly coupled, and m=+1 (right-hand) waves are necessary for good plasma production. Loading results indicate that antennas also couple to absorption mechanisms unrelated to helicon waves.