The beta of a plasma, symbolized by β, is the ratio of the plasma pressure (p = n k_B T) to the magnetic pressure (p_mag = B²/2μ₀). A plasma lamp, illustrating some of the more complex phenomena of a plasma, including filamentation. ... The use of water pressure - the Captain Cook Memorial Jet in Lake Burley Griffin, Canberra. ... Density, or volumic mass (ISO 31), is a measure of mass per unit volume. ... The Boltzmann constant (k or kB) is the physical constant relating temperature to energy. ... Fig. ... Magnetic Pressure is the pressure applied by a magnetic field on to the container that is containing the magnetic field. ... Current (I) flowing through a wire produces a magnetic field () around the wire. ... In electromagnetism, permeability is the degree of magnetisation of a material that responds linearly to an applied magnetic field. ...

Beta is a parameter indicating the relative importance of kinetic to electromagnetic phenomena. In fusion power applications, beta can be thought of as an economic figure of merit. The magnetic field in a fusion device has technological limits such as the critical field of practical superconductors. The fusion power density, which determines the power output of a reactor, scales with the square of the plasma pressure. Therefore the output of a reactor can be said to scale with the square of the average beta. In a tokamak, for example, there is a fairly firm limit on the value beta can have before destructive instabilities occur. The Sun is a natural fusion reactor. ... Superconductivity is a phenomenon occurring in certain materials at low temperatures, characterised by the complete absence of electrical resistance and the damping of the interior magnetic field (the Meissner effect. ... A split image of the largest tokamak in the world, the JET, showing hot plasma in the right image during a shot. ...