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Magnetic compression heating of extremely high beta plasma configuration

极高 β 等离子体配置的磁压缩加热

基本信息

批准号：
12480119
负责人：
OKADA Shigefumi
金额：
$ 8.06万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2002
项目状态：
已结题

项目摘要

Plasma with field-reversed configuration has extremely high beta value (plasma pressure/ confining magnetic field pressure) of about 1. Therefore, confining magnetic field of the FRC fusion reactor can be far weaker than in low beta confinement schemes, which is favorable for technological viewpoint. High-energy neutral beam (NB) is the most important method to heat and sustain the FRC plasma. As the cost of the NB is expensive, it is desired that the FRC plasma should have good confinement property to reduce the cost of the NB. It is known that confinement time of the FRC plasma is proportional to 2-3 powers of the radius r_s of the FRC plasma. Up to present, r_s has increased by translating the plasma from formation region to confinement region. This technology of translation has an advantage that r_s can be increased without serious lowering of plasma temperature. But it has a disadvantage that obtainable value of r_s is limited: By the translation, the FRC plasma is ejected into th … More e confinement region with supersonic velocity and it must be stopped, when the plasma expands radially, excessively and the confinement is degraded because, perhaps, the plasma touches the wall. In order to increase r_s, new scheme of axial compression is proposed. The FRC plasma is compressed radially by decreasing the distance between the mirror fields, which are confining the plasma. Coils were developed to realize this compression, which coils produced magnetic field with the rise time of about 50μs, which is faster than confinement times and slower than propagation of sound wave. These coils were installed in the vacuum chamber and were energized successively. The result of the compression could be explained by adiabatic theory when the effect of energy loss and the magnetic flux loss were token into account. Moreover, it was also observed that the confinement property did not depend on the plasma length even when the plasma was compressed until the elongation (plasma length / plasma radius) or the aspect ratio became as small as 4.1. Less

具有场反转配置的等离子体具有约1的极高的β值（等离子体压力/约束磁场压力）。因此，FRC聚变反应堆的约束磁场可以远弱于低β约束方案，这有利于技术观点。高能中性束（NB）是加热和维持FRC等离子体最重要的方法。由于NB的成本昂贵，因此期望FRC等离子体应当具有良好的约束特性以降低NB的成本。已知FRC等离子体的约束时间与FRC等离子体半径rs的2-3次方成正比。到目前为止，通过将等离子体从形成区平移到约束区，r_s增加。这种平移技术的优点是可以在不严重降低等离子体温度的情况下提高r_s。但它也有一个缺点，即可获得的r_s值有限：通过平移，FRC等离子体被喷射到 ...更多信息当等离子体径向膨胀过度时，必须停止，并且约束会因为等离子体可能接触壁而退化。为了提高抗弯强度，提出了轴压方案。FRC等离子体通过减小限制等离子体的镜场之间的距离而径向压缩。为了实现这种压缩，开发了线圈，线圈产生的磁场的上升时间约为50μs，这比约束时间快，比声波的传播慢。这些线圈被安装在真空室中并被连续地通电。在考虑能量损失和磁通损失的情况下，可以用绝热理论解释压缩的结果。此外，还观察到，即使当等离子体被压缩直到伸长（等离子体长度/等离子体半径）或纵横比变得小到4.1时，约束特性也不依赖于等离子体长度。少