Reversed field pinch
The term reversed field pinch ( RFP ) describes a system for locking in fusion plasma . She is a toroidal pinch (Engl. For Quetsche ) having a unique magnetic field configuration used to imprison plasma magnetic. It is mainly used for fusion research .
description
The magnetic field geometry of an RFP is a little different from the more popular tokamak . When moving radially outward, the toroidal component of the magnetic field reverses direction. This property is described by the name part reversed field . Compared to the tokamak, this configuration manages with weaker magnetic fields with the same energy density. A disadvantage of this type of system is that it tends to produce larger non-linear effects and turbulence. This makes it the ideal device to study non-ideal ( resistive ) magnetohydrodynamics . RFPs are also used to study astrophysical plasma because they have many similarities.
The largest reversed field pinch system currently in operation is the “ Reversed-Field eXperiment ”. Other systems include the Madison Symmetric Torus, EXTRAP T2R in Sweden, TPE-RX in Japan, and Keda Torus eXperiment (KTX) in China.
properties
In contrast to the tokamak, which uses much stronger magnetic fields in the toroidal than in the poloidal direction, in the RFP the field strengths are comparably strong in both directions (although the sign changes in the toroidal direction). In addition, the RFP has a field strength of approximately one tenth to one half of a comparable tokamak. In addition, the RFP is based on the induction of current into the plasma to strengthen the field of magnets through a dynamo effect .
advantages
An RFP offers several potential advantages. One advantage is that there is no known β limit. β is a parameter that relates the average pressure gradient to the magnetic field strength. For practical purposes, β can be viewed as a concept of relative efficiency (this is not exactly true, but can serve as an estimate).
- natural plasma
- economically
- compact
- high energy density (minimal energy, stable)
- ignites without external heating of the plasma
Magnetic topology
The RFP works on the principle of minimum energy, i. That is, the potential energy of a charged moving particle along a line in the RFP is minimal.
The magnetic field lines wrap loosely around the center of a torus . The toroidal magnetic field is reversed within the plasma ring. The field lines continue to wind in the opposite direction.