This radiation is produced by relativistic electrons spiralling in a magnetic field

This radiation is produced by relativistic electrons spiralling in a magnetic field

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This radiation is produced by relativistic electrons spiralling in a magnetic field. We see only the electrons; protons are less efficient radiators by a factor m p /m e . The electrons undergo acceleration a =(e/m) v x B where all three quantities are vectors (this is the relativistic Lorentz force). The particle path is a slowly widening helix. A distant observer sees pulses of radiation, beamed into a cone by the Lorentz transformation. Radiation from monoenergetic electrons is spread by this process over a large frequency range, as shown in Fig. 7 of the Ginzburg & Syrovatskii 1965 review (from the ADS): peaked at in which B is the field intensity modulated by the sine of the pitch angle of motion with respect to the field lines. The particle distribution in angle needs to be known - a frequent assumption is that of pitch angle scattering happening rapidly compared to the radiative-loss rate. Observed sources generally have a power-law spectrum F ν = F 0 ν α with α ~ 0.7; α is the spectral index.
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This note was uploaded on 11/10/2011 for the course AST AST1002 taught by Professor Emilyhoward during the Fall '10 term at Broward College.

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This radiation is produced by relativistic electrons spiralling in a magnetic field

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