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在HL-1M实验中,多发弹丸注入到欧姆加热放电中,明显改善了等离子体约束特性。与相同条件下的欧姆加热放电相比,能量约束时间提高了约30％。等离子体约束的改善是因为弹丸注入后在等离子体中心区域形成了高度峰化的密度和压强分布。实验发现弹丸穿透的深度决定了密度和压强分布的峰化程度,而等离子体中心的磁流体力学活性又随着密度和压强分布的峰化程度的增大而改变。另一方面,等离子体中心磁流体动力学(MHD)活性在限制可达到的中心等离子体压强和决定中心输运特性上起着重要作用,标志着弹丸注入约束改善的峰化的密度、压强分布在出现第一个大锯齿后平化。随着弹丸穿透的加深,芯部区域的压强(密度)梯度变陡,中心MHD活性受到弹丸注入的强烈影响,锯齿崩溃特征有在更高密度、更高压强下时才出现的类理想模的特性,并在崩溃过程中m=1模的发展与一个非常定域的压强扰动耦合。
In the HL-1M experiment, multiple projectiles were injected into the ohmic heating discharge, which significantly improved the plasma confinement properties. Compared with the ohmic heating discharge under the same conditions, the energy confinement time is increased by about 30%. Plasma confinement is improved because of the highly-peculiar density and pressure distribution in the central plasma region after projectile injection. It is found that the penetration depth of the projectile determines the degree of peaking of the density and pressure distribution, and the magnetohydrodynamic activity of the plasma center changes with the increase of the peaking degree of density and pressure distribution. On the other hand, plasma center MHD activity plays an important role in limiting attainable central plasma pressure and determining central transport properties, indicating that the pellet injection constraints improve the peaking density, pressure distribution Flattened after the first large sawtooth. With the deepening of projectile penetration, the gradient of density (density) in the core region becomes steep, and the center MHD activity is strongly influenced by the projectile injection. The serrated collapse features are of the ideal type that occurs at higher densities and pressures The characteristics of m = 1 and the coupling of a very localized pressure disturbance during the collapse process.