Production of Highly Overdense Uniform Plasma with a large Area by ECH.

将电子回旋共振加热与线性多极磁场相结合，可以获得大面积、高密度、均匀的等离子体。等离子体的电子密度和电子温度应易于控制，并易于与任何种类的气体保持。根据2450 MHz射频脉冲源产生等离子体的研究经验，研究了等离子体化学气相沉积（CVD）所需的稳定工作装置。为了减少电流以产生ECH所需的磁场强度，采用了430 MHz的RF功率。结果，已经实现了具有高达2x 1011 cm-3的电子密度的静止等离子体，该密度对应于所使用频率的截止密度的一百倍。也许，这将是第一个实验，以显示一个明确的结果，ECR加热与如此低的频率。这是由于多极结构具有良好的等离子体约束特性。除了物理上的这些结果外，还利用多极子得出结论，在无磁场区原则上可以形成真正均匀的等离子体。如果需要，可以通过增加极数来产生更宽的均匀等离子体。

By combining an electron cyclotron resonance heating with a linear multipole magnetic field configuration, high density uniform plasmas with a large area has been asked. The plasma should be easily controllable in electron density and electron temperature and maintained easily with any kinds of gases. On the research experience to produce plasma with 2450 MHz RF source in a pulse mode operation, an equipment in steady operation necessary for applications to plasma CVD has been studied. To reduce the current to produce a magnetic field intensity necessary for ECH,an RF power of 430 MHz has been employed. As a result, stationary plasmas with electron density of as much as 2x1011 cm-3 has been realized, which density corresponds to a hundred times of the cut-off density of the used frequency. Probably, this will be the first experiment to show a clear results of ECR heating with such a low frequency. This is owing to the excellent plasma confinement characteristics of multipole configuration. Besides of this results in physics, it has been concluded by using a multipole that a truly uniform plasma can be formed in magnetic field-free zone in principle. If necessary, it is easily realized by increasing the pole number to produce a wider uniform plasma.