Thermal-barrier experiments in the Tandem Mirror Experiment Upgrade (TMX-U) are reported, along with progress made at the Lawrence Livermore National Laboratory in plasma confinement and central-cell heating. Thermal barriers in TMX-U improved axial confinement by two orders of magnitude over a limited range of densities, compared with confinement in single-cell mirrors at the same ion temperature. It is shown that central-cell radial nonambipolar confinement scales as neoclassical theory and can be eliminated by floating the end walls. Radial ambipolar losses can also be measured and reduced. The electron energy balance is improved in tandem mirrors to near classical, resulting in T/sub e/ up to 0.28 keV. Electron cyclotron heating (ECH) efficiencies up to 42%, with low levels of electron microinstability, were achieved when hot electrons in the thermal barrier were heated to average betas as large as 15%. The hot-electron distribution was measured from X-rays and is modeled by a Fokker-Planck code that includes heating from cavity radio-frequency (RF) fields.
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机译：报告了串联镜实验升级版（TMX-U）中的热障实验，以及劳伦斯·利弗莫尔国家实验室在血浆限制和中央细胞加热方面的进展。与在相同离子温度下在单池反射镜中进行限制相比，TMX-U中的热障在有限的密度范围内将轴向限制提高了两个数量级。结果表明，中心细胞径向非双极性约束的尺度是新古典理论，可以通过浮置端壁来消除。径向双极损耗也可以测量和减少。串联反射镜中的电子能量平衡提高到接近经典水平，导致T / sub e /高达0.28 keV。当将热障中的热电子加热到平均β高达15％时，电子回旋加速器加热（ECH）的效率高达42％，而电子微不稳定性较低。根据X射线测量热电子分布，并通过Fokker-Planck编码对模型进行建模，该编码包括空腔射频（RF）场的加热。
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