### Abstract

In this paper, we discuss a new cyclotron maser type instability driven by a crescent or horseshaped electron distribution function. Such distribution functions are easily created by an electron beam moving into a stronger magnetic field region, where conservation of the first adiabatic invariant causes an increase in their pitch angle. This produces a broad region on the distribution function where ∂fe/∂v⊥ > 0. Planetary dipole magnetic fields are examples of where these types of distributions can be found. We examine the stability of these electron horseshoe distribution functions for right-hand extraordinary mode (R–X mode) radiation close to the electron cyclotron frequency propagating perpendicular to the magnetic field using both non-relativistic and relativistic beams.

Original language | English |
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Pages (from-to) | 160-162 |

Number of pages | 3 |

Journal | Physica Scripta |

Volume | T98 |

DOIs | |

Publication status | Published - 2002 |

### Keywords

- microinstabilities
- plasma interactions
- radiation mechanisms
- polarization

## Cite this

Bingham, R., & Cairns, R. A. (2002). A new cyclotron maser radiation mechanism in space plasmas.

*Physica Scripta*,*T98*, 160-162. https://doi.org/10.1238/Physica.Topical.098a00160