Electron-Cyclotron Maser Instability Driven by a Loss-Cone Distribution

1983 ◽  
Vol 50 (4) ◽  
pp. 243-246 ◽  
Author(s):  
Y. Y. Lau ◽  
K. R. Chu
Keyword(s):  
Electron Cyclotron ◽  
Loss Cone ◽  
Electron Cyclotron Maser ◽  
Cyclotron Maser

scholarly journals Radio Emission from Ultrashort-Period Double Degenerate Binaries

2004 ◽  
Vol 21 (3) ◽  
pp. 248-251 ◽  
Author(s):  
A. J. Willes ◽  
K. Wu ◽  
Z. Kuncic
Keyword(s):  
Radio Emission ◽  
Flux Tube ◽  
Current System ◽  
Electron Cyclotron ◽  
Loss Cone ◽  
X Ray ◽  
Electron Cyclotron Maser ◽  
Cyclotron Maser ◽  
Theoretical Predictions ◽  
Orbital Periods

AbstractTiming measurements of periodic X-ray pulses from two ultrashort-period double degenerate binaries, RX J1914+24 and RX J0806+15, show that the rates of change of their orbital periods are consistent with gravitational radiation losses. This contradicts the predictions of models which invoke mass transfer between the two white dwarfs. The X-ray emission is, therefore, unlikely to be powered by accretion processes. The unipolar inductor model explains the source of X-ray emission as electrical dissipation at the base of a flux tube, which connects the magnetic white dwarf to its companion. This model is most consistent with the observed X-ray pulse properties. A similar current system exists in the Jupiter–Io system, where a mildly relativistic electron current produces an auroral footprint at the base of the Io flux tube and highly polarized beamed radio emission by means of the electron cyclotron maser mechanism. Detection of radio emission from RX J1914+24 and RX J0806+15 would thus provide further support for the unipolar inductor model. We present theoretical predictions, based on a loss-cone-driven electron cyclotron maser model, of radio fluxes from systems with parameters similar to RX J1914+24 and RX J0806+15.

Electron-cyclotron maser theory for extraordinary Bernstein waves

1997 ◽  
Vol 58 (1) ◽  
pp. 171-191 ◽  
Author(s):  
A. J. WILLES ◽  
P. A. ROBINSON
Keyword(s):  
Electron Distribution ◽  
Electron Cyclotron ◽  
Loss Cone ◽  
Wave Growth ◽  
Electron Cyclotron Maser ◽  
Cyclotron Maser ◽  
Hybrid Frequency ◽  
Bernstein Waves ◽  
Bernstein Wave ◽  
Cyclotron Harmonic

Electron-cyclotron maser emission is investigated in the regime where wave growth in the electrostatic Bernstein modes dominates (ωp/Ωe>1.5). A semirelativistic growth rate is derived assuming that the wave dispersion is dominated by a cool background electron distribution and the instability is driven by a low-density hot loss-cone-like electron distribution. The properties of Bernstein wave growth are most strongly dependent on the relative temperatures of the hot and cool electron distributions. For Thot/Tcool[gsim ]10, the fastest growing Bernstein waves are produced at frequencies just below each cyclotron harmonic in Bernstein modes lying below the upper-hybrid frequency. For Thot/Tcool[lsim ]10, additional Bernstein modes above the upper-hybrid frequency are excited, with wave frequencies in each excited mode lying significantly above the corresponding cyclotron harmonic. The dependence of Bernstein wave growth on the relative hot and cool electron number densities and emission angle is also discussed.

scholarly journals The Loss-cone Driven Electron-cyclotron Maser

1982 ◽  
Vol 35 (4) ◽  
pp. 447 ◽  
Author(s):  
RG Hewitt ◽  
DB Melrose ◽  
KG Rönnmark
Keyword(s):  
Relativistic Correction ◽  
Electron Cyclotron ◽  
Important Class ◽  
Instability Mechanism ◽  
Loss Cone ◽  
Radio Emissions ◽  
Electron Cyclotron Maser ◽  
Cyclotron Maser ◽  
Class B

Electron-cyclotron instabilities may be classified in two ways depending on whether the relativistic correction to the gyrofrequency is important (class S) or not (class N), and whether the instability mechanism is of a maser type (class M) or due to bunching (class B). Renewed interest in class SM has followed the Wu and Lee application of it to the interpretation of terrestrial kilometric radiation. The maser is assumed to be driven by a one-sided loss-cone distribution of electrons. This mechanism seems particularly favourable for the interpretation of certain planetary, solar and stellar radio emissions

Kinematic and temperature restrictions on the electron cyclotron maser instability

1986 ◽  
Vol 36 (1) ◽  
pp. 63-74 ◽  
Author(s):  
P. A. Robinson
Keyword(s):  
Growth Rate ◽  
Refractive Index ◽  
Wave Propagation ◽  
Distribution Function ◽  
Electron Cyclotron ◽  
Harmonic Number ◽  
Loss Cone ◽  
Propagation Angle ◽  
Electron Cyclotron Maser ◽  
Cyclotron Maser

The ranges of temperature T, harmonic number s and wave propagation angle θ in which the loss-cone-driven electron cyclotron instability can exist are found to be limited by opposing contributions to the growth rate from adjacent harmonics. For waves with refractive index n ⋍ 1 it is found that instability is possible only if T and s satisfy saT ≲ C with a = 2 − 2·5 and where the constant C is determined by θ and the form of the distribution function. It is argued that the corresponding restrictions for waves with very large or very small n are less severe. Instability is found to be forbidden for waves propagating outside a range |θ − 90°| < φ(s), except if θ ⋍ 0, where π(s) is independent of temperature and sin2φ(s) ⋍ s−1; this restriction limits the range of potentially unstable frequencies at a given harmonic.

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