It has been known that the width of the trapped particles, i.e. bananas, is reduced or squeezed in a magnetic well in tokamaks. The magnetic squeezing factor S _B depends on the energy and pitch angle of the particles. When ρ _p/a ∼ 1, S _B becomes appreciably larger than unity; it can be of the order of 2 for a parabolic well with B ⁻¹ d² B/dr ² ∼ 2a ⁻². Here, ρ _p is the poloidal gyro-radius, B is the magnetic field strength, r is the local minor radius, and a is the minor radius. However, the real orbit width measured in terms of the poloidal magnetic flux is still less than a because of the magnetic squeezing; for S _B = 2, it is a 30% reduction. The transport consequences of the squeezed bananas in a magnetic well are calculated by solving the drift kinetic equation utilizing the constants of motion in the large aspect ratio limit. Consequently, neoclassical ion heat conductivity χ _h in the reactor relevant collisionality regime (i.e. banana regime) is reduced by a factor of ; for S _B = 2, it is almost a factor of three reduction for the same temperature. The ion temperature scaling of χ _h improves from the conventional, and weakly favorable scaling to the strongly favorable scaling for high temperature fusion grade tokamak plasmas; the scaling however does not take the temperature dependence of the magnetic well itself into account. Here, T _i is the ion temperature. In addition, it is shown that plasma turbulence is suppressed in a magnetic well using the reduced decorrelation time argument and anomalous plasma confinement is improved. The combined improvements result in a favorable temperature scaling in the ion energy confinement time, and make burning aneutronic fuels feasible. The implications on a tokamak with a magnetic well as a fusion reactor are discussed.

众所周知，在托卡马克的磁井中，被捕获的颗粒（即香蕉）的宽度会减小或被挤压。磁挤压因子S _B取决于粒子的能量和俯仰角。当ρ _p / a ∼ 1 时，S _B明显大于 unity；对于具有B ^-1  d ² B /d r ² ∼ 2 a ^-2的抛物线阱，它可以是2的数量级。这里，ρ _p是极向陀螺半径，B是磁场强度，r是局部小半径，并且 a是小半径。然而，由于磁挤压，用极向磁通测量的实际轨道宽度仍然小于α；对于S _B = 2，减少 30%。通过利用大纵横比极限中的运动常数求解漂移动力学方程，可以计算在磁井中挤压香蕉的输运后果。因此，反应堆相关碰撞状态（即香蕉状态）中的新经典离子热导率χ _h降低了；对于S _B = 2，对于相同的温度，它几乎是减少的三倍。χ _h的离子温度标度 对于高温聚变级托卡马克等离子体，从传统的弱有利结垢改进为强有利结垢；然而，缩放没有考虑磁阱本身的温度依赖性。这里，T _i是离子温度。此外，还表明使用减少的去相关时间参数抑制了磁阱中的等离子体湍流，并改善了异常等离子体限制。综合改进导致离子能量限制时间的有利温度缩放，并使非中子燃料的燃烧成为可能。讨论了对具有磁井的托卡马克作为聚变反应堆的影响。