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A magnetic mirror is a magnetic field configuration where the field strength changes when moving along a field line. The mirror effect results in a tendency for charged particles to bounce back from the high field region. To meet Wikipedias quality standards, this article may require cleanup. ...
Charged particles with a velocity component perpendicular to the field will gyrate around a field line in a generally circular or helical orbit and thus sample some of the field lines that are converging to create the field gradient. The radial component of these field lines, coupled with the azimuthal motion of the particle, will result in a force parallel to the field and directed toward the region of smaller field strength.
A more mathematical treatment of the mirror effect describes it as a result of the adiabatic invariance of the magnetic moment. For a given mirror ratio (the maximum field strength dividņşed by the minimum field strength), particles with a pitch angle (angle between the particle velocity and the magnetic field) greater than a critical value will be reflected, those with a smaller pitch angle will escape. In particular, An adiabatic invariant in general is a property of motion which is conserved to exponential accuracy in the small parameter representing the typical rate of change of the gross properties of the body. ...
 This result may be surprising because one might intuitively expect that heavier and faster particles, or those with less electric charge, would be harder to reflect, or that a smaller magnetic field would reflect particles less efficiently. However, it must be remembered that the gyroradius ρ = mv/qB in those circumstances is also larger, so that the radial component of the magnetic field seen by the particle is also larger. It is true that the minimum volume and magnetic energy is larger for the case of fast particles and weak fields, but the mirror ratio required remains the same. A Plasma lamp, illustrating some of the more complex phenomena of a plasma, including filamentation A solar coronal mass ejection blasts plasma throughout the solar system. ...
In the sixties and seventies, machines using magnetic mirror confinement were considered a viable candidate for producing fusion energy. The concept was eventually abandoned because it proved to be impractical to maintain the necessary non-Maxwellian velocity distribution. The Sun is a natural fusion reactor. ...
Magnetic mirrors play an important role in other types of magnetic fusion energy devices such as tokamaks, where the toroidal magnetic field is stronger on the inboard side than on the outboard side. The resulting effects are known as neoclassical. Magnetic Fusion Energy (MFE) is a sustained nuclear fusion reaction in a plasma that is contained by magnetic fields. ...
A split image of the largest tokamak in the world, the JET, showing hot plasma in the right image during a shot. ...
Magnetic mirrors also occur in nature. Electrons and ions in the ionosphere, for example, will bounce back and forth between the stronger fields at the poles. Relationship of the atmosphere and ionosphere The ionosphere is the part of the atmosphere that is ionized by solar radiation. ...
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