MHD Relaxation: Magnetic Self-Organization

Magnetized fluids and plasmas are observed to exist naturally in states that are relatively independent of their initial conditions or the way in which the system was prepared. Their properties are completely determined by boundary conditions and a few global parameters, such as magnetic flux, current, and applied voltage. Successive experiments carried out with the same global parameters yield the same mean state, even though they were not initiated in exactly the same way (for example, how the gas initially fills the vacuum chamber or the breakdown process). Further, if the system is disturbed it tends to return to the same state. These preferred states are called relaxed, or self-organized, states, and the dynamical process of achieving these states is called plasma relaxation, or self-organization. Relaxed states cannot result from force balance or stability considerations alone, because there may be many different stable equilibria corresponding to a given set of parameters and boundary conditions. Some other process must be at work.