Theoretical and experimental research in the reversed-field pinch (RFP) is reviewed. In this system, Bθ ∼ Bϕ, q < 1 and Bϕ reverses in the outer regions of the plasma; stability at relatively high values of β is possible because there is high shear and, experimentally, confinement with β > 10% has been observed. Following a historical review of pinch research, the basic theoretical properties of the RFP are established including the equilibrium, toroidal displacement, diffusion and confinement; studies of ideal and dissipative MHD stability theory are then described. Experimental and theoretical work on relaxation and self-reversal, the process whereby an RFP distribution can be set up spontaneously and subsequently sustained, is presented and discussed. There follows a general account of RFP experiments. These are divided into 'fast experiments', which utilize small-bore insulating tori in which the distribution is usually set up by fast programming on microsecond timescales, and 'slow experiments', carried out in large metal-walled tori in which the field configuration is set up slowly by self-reversal on millisecond timescales. A brief account of RFP reactor studies and of new and future experiments is then given, followed finally by a general discussion in which the main conclusions are presented.
反场箍缩（RFP）中的理论与实验研究综述。在该系统中，Bθ ∼ Bϕ，q < 1，且Bϕ在等离子体外部区域发生反转；由于存在高剪切，系统能够在相对较高的β值下保持稳定，并且实验中已观察到β > 10%的约束。在回顾箍缩研究的历史之后，确立了RFP的基本理论性质，包括平衡、环向位移、扩散与约束；随后描述了理想和耗散磁流体力学（MHD）稳定性理论的研究。接着介绍了关于弛豫和自反转的实验与理论工作，即RFP分布如何被建立并随后自发维持的过程。之后对RFP实验进行了总体概述，将其分为“快实验”和“慢实验”两类：前者利用小孔径绝缘环，通常通过微秒时间尺度的快速编程来建立分布；后者则在大孔径金属壁环中进行，场位形通过毫秒时间尺度的自反转缓慢建立。最后简要介绍了RFP反应堆研究以及新的和未来的实验，并给出了主要结论的总体讨论。