We have investigated three basic forms of drift motion: electric drift, centrifugal drift, and gradient drift. These are described completely by the motion of particles in time-independent electric and magnetic fields which vary slowly in space. In addition there are possible drifts caused by extraneous nonelectrical forces, e.g., the force of gravity. All of these excite drift currents. If the particles experience a constant or slowly varying acceleration, then motion will result as though under the action of an inertial force equal to the product of the mass and acceleration. This force gives rise to an inertial drift and to a corresponding drift current. An especially important case, in which acceleration results from a change in the rate of electrical drift, is caused by variations in the electric field. This particular case of inertial drift is therefore called the polarization drift. This name is significant since the cause of the acceleration is the change in the electric field inside the plasma. This usually results, not so much from an external field, but from polarization of the plasma due to charge separation within the plasma itself.
KeywordsMagnetic Field Inertial Force Drift Concept Radial Electric Field Drift Current
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