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The equatorial pitch angle of a particle is the pitch angle of the particle at the Earth's geomagnetic equator. This angle defines the loss cone of a particle. The loss cone is the set of angles where the particle will strike the atmosphere and no longer be trapped in the magnetosphere while
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582:{\displaystyle \mu ={\frac {1}{2}}{\frac {mv_{\perp 0}^{2}}{B_{0}}}={\frac {1}{2}}{\frac {mv^{2}\sin ^{2}\left(\alpha _{0}\right)}{B_{0}}}={\frac {1}{2}}{\frac {mv^{2}}{B_{m}}}}
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It is customary to discuss the direction a particle is heading by its pitch angle. A pitch angle of 0 degrees is a particle whose parallel motion is perfectly along the local
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is the field strength at the mirror point. Notice that this is independent of charge, mass, or kinetic energy.
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284:{\displaystyle {\begin{aligned}\sin ^{2}\left(\alpha _{0}\right)={\frac {B_{0}}{B_{m}}}\end{aligned}}}
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This article is about the pitch angle of a charged particle. For Pitch angle in engineering, see
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this particle would be heading down toward the Earth (and the opposite in the
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is the equatorial magnetic field strength at the surface of the earth, and
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is the angle between the particle's velocity vector and the local
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particles with pitch angles outside the loss cone will
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196:Special case: equatorial pitch angle
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380:invariance of the magnetic moment
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314:{\displaystyle \alpha _{0}}
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