The reversed field pinch

These notes are based on lectures given by one of us (J.B.T.) at the University of Texas in Austin in 1991. Part I concerns some basic features of plasma confinement by magnetic fields as an introduction to an account of plasma relaxation in Part II. Part III discusses confinement by magnetic mirrors, especially minimum-B systems. It also includes a general discussion of adiabatic invariants and of the principle of maximal ordering in perturbation theory. Part IV is devoted to the analysis of perturbations in toroidal plasmas and the stability of ballooning modes. PREFACEThe theory of plasma confinement is complicated and incomplete. Because current textbooks do not include material at the frontier of research, it is hard for students and researchers to become familiar with the state of the art. Bryan Taylor's notes are presented here to start filling that gap. Although based on lectures from over twenty years ago, they provide much needed clarity in selected areas of current plasma confinement research. Of course much of the original work on which these notes are based is by Bryan Taylor and collaborators; but here, he and Sarah Newton draw the many threads together. Indeed, while some may find the results familiar, the insight is fresh and enlightening. The research frontier is just beyond these notes. Some of the outstanding questions are posed and some are left to the reader to discern. For example, we still need to know: how fast plasmas relax; how three-dimensional reconnection works; how ballooning modes saturate and; how minimum B ideas can improve toroidal devices. The insights here will help anyone wanting to answer those and other questions.

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“…The Bessel profile fits the experimental data remarkably well, as can be seen in figure 19 and in Bodin (1983Bodin ( , 1984Bodin ( , 1987.…”

Section: Relaxed States In Toroidal Pinchsupporting

confidence: 57%

“…This corresponds to an experimental pinch parameter θ > 1.2 -which again agrees well with the experimental observations. Bodin (1984). )…”

Section: Spontaneous Field Reversalmentioning

confidence: 98%

Special topics in plasma confinement

Taylor

Newton

2015

J. Plasma Phys.

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“…This prediction explains a remarkable common feature of both RFP and spheromak plasmas, that after an initial highly turbulent state, the plasma settles into a more quiescent state in which µ tends to be spatially uniform (Bodin, 1990;Bellan, 2000).…”

Section: A Sawtooth Reconnection In Tokamaksmentioning

confidence: 78%

Magnetic Reconnection

Yamada¹

2009

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We review the fundamental physics of magnetic reconnection in laboratory and space plasmas, by discussing results from theory, numerical simulations, observations from space satellites, and the recent results from laboratory plasma experiments. After a brief review of the well-known early work, we discuss representative recent experimental and theoretical work and attempt to interpret the essence of significant modern findings. In the area of local reconnection physics, many significant findings have been made with regard to two-fluid physics and are related to the cause of fast reconnection. Profiles of the neutral sheet, Hall currents, and the effects of guide field, collisions, and micro-turbulence are discussed to understand the fundamental processes in a local reconnection layer both in space and laboratory plasmas. While the understanding of the global reconnection dynamics is less developed, notable findings have been made on this issue through detailed documentation of magnetic self-organization phenomena in fusion plasmas. Application of magnetic reconnection physics to astrophysical plasmas is also briefly discussed.

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“…1), where most of relevant theoretical and experimental dynamo work have been performed. Specifically, the reversed-field pinch (RFP) plasmas [4,5] shall be described in detail. A similar configuration known as spheromak [6,7] shall also be mentioned but the interested readers should refer to the review papers mentioned above for some experimental details.…”

Section: Pinch Plasmas: Magnetically Driven Systemsmentioning

confidence: 99%

The Alpha Dynamo Effects in Laboratory Plasmas

Ji¹,

Prager²

2001

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A concise review of observations of the α dynamo effect in laboratory plasmas is given. Unlike many astrophysical systems, the laboratory pinch plasmas are driven magnetically. When the system is overdriven, the resultant instabilities cause magnetic and flow fields to fluctuate, and their correlation induces electromotive forces along the mean magnetic field. This α-effect drives mean parallel electric current, which, in turn, modifies the initial background mean magnetic structure towards the stable regime. This drive-andrelax cycle, or the so-called self-organization process, happens in magnetized plasmas in a time scale much shorter than resistive diffusion time, thus it is a fast and unquenched dynamo process. The observed α-effect redistributes magnetic helicity (a measure of twistedness and knottedness of magnetic field lines) but conserves its total value. It can be shown that fast and unquenched dynamos are natural consequences of a driven system where fluctuations are statistically either not stationary in time or not homogeneous in space, or both. Implications to astrophysical phenomena will be discussed.

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The reversed field pinch

Cited by 145 publications

References 59 publications

Special topics in plasma confinement

Special topics in plasma confinement

Magnetic Reconnection

The Alpha Dynamo Effects in Laboratory Plasmas

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