Plasma physics

Plasmas are conductive assemblies of charged particles, neutrals and fields that exhibit collective effects. Further, plasmas carry electrical currents and generate magnetic fields. Plasmas are the most common form of matter, comprising more than 99% of the visible universe, and permeate the solar system, interstellar and intergalactic environments.

Plasmas are radically multiscale in two senses
(1) most plasma systems involve electro-dynamic coupling across micro-, meso- and macroscale and (2) plasma systems occur over most of the physically possible ranges in space, energy and density scales. The figure here illustrates where many plasma systems occur in terms of typical densities and temperatures.
Contemporary Physics Education Project

However, the full range of possible plasma density, energy(temperature) and spatial scales go far beyond this illustration. For example, some space plasmas have been measured to be lower in density than 10 to the power -10 per cubic meter or (10exp-10)/m3 - 13 orders of magnitude less than the scale shown in the figure! On the other extreme, quark-gluon plasmas (although mediated via the strong force field versus the electromagnetic field) are extremely dense nuclear states of matter. For temperature (or energy), some plasma crystal states produced in the laboratory have temperatures close to absolute zero. In contrast, space plasmas have been measured with thermal temperatures above 10+9 degrees Kelvin and cosmic rays (a type of plasma with very large gyroradii) are observed at energies well above those produced in any man-made accelerator laboratory. Considering Powers of 10 is useful for grasping the unique way in which plasmas are radically multi-scale in space, energy and density.