Electron-cyclotron masers as the source of certain solar and stellar radio bursts

Melrose, D. B.; Dulk, G. A.

doi:10.1086/160219

Cited by 462 publications

(347 citation statements)

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“…The data collected to date, suggest that the pulses are produced at the poles by the electron cyclotron maser (hereafter ECM) instability, the same mechanism known to be responsible for the radio emission from the magnetized planets in our solar system (Zarka 1998). This mechanism is also the source of certain classes of solar and stellar bursts (Melrose & Dulk 1982;Bingham et al 2001;. It was also suggested to be operational in the magnetic chemically peculiar star CU Vir where 100% circularly polarized, bright and highly directive radio bursts were detected (Kellett et al 2007;Trigilio et al 2007), and for the compact binary RX J080 6.3+1527 (Ramsay et al 2007).…”

Section: Introductionmentioning

confidence: 97%

Phase connecting multi-epoch radio data for the ultracool dwarf TVLM 513-46546

Doyle¹,

Antonova

Marsh

et al. 2010

A&A

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Context. Radio data obtained for the ultracool dwarf TVLM 513-46546 has indicated a rotation period of ≈1.96 h via regular radio pulses, but how stable is this period. This has major implications regarding the stability of the magnetic field structures responsible for the radio emission from the ultracool dwarf. Aims. The aim of the present work is to investigate the stability of this rotation period using two datasets taken ≈40 days apart, some 12 months after the first report of periodical pulses in the radio data. Methods. Here we use a Bayesian analysis method which is a statistical procedure that endeavours to estimate the parameters of an underlying model probability distribution based on the observed data. Results. Periodical pulses are detected in datasets taken in April and June 2007, with the pulses being confined to a narrow range in the rotation period. This is in contradiction to a previous report of only aperiodic activity in the April 2007 dataset, while in fact both datasets have a periodic signal with a false alarm probability 10 −12 . These two datasets are then used to derive a more accurate period (previously determined to be 1.96 h) of 1.96733 ± 0.00002 h. Conclusions. The similarly in the burst structure in datasets taken several weeks apart point towards the stability of an electric field structure which is somehow generated and sustained within the magnetosphere of the ultracool dwarf. The derived period of 1.96733 h is consistent with the period derived via radio and optical data taken some 12 months prior to the present observations and implies the near phase constancy of the pulsed emission. This suggest the presence of stable large-scale magnetic fields on timescales of more than 1 year. The characteristics of the pulses suggest that they are produced by the electron cyclotron maser (ECM) instability.

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Section: Introductionmentioning

confidence: 97%

Phase connecting multi-epoch radio data for the ultracool dwarf TVLM 513-46546

Doyle¹,

Antonova

Marsh

et al. 2010

A&A

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“…Two different spike locations are predicted by the theories of spike emission. In theories proposing electron cyclotron maser-emission caused by loss-cone instability of trapped electrons (e.g., Holman et al 1980;Melrose & Dulk 1982;Fleishman & Yastrebov 1994), the emission would be expected to originate in regions close to the footpoints of a magnetic loop. In the other theories, spike sources are proposed to result from waves produced in the acceleration process and would therefore be expected to originate from the location of the acceleration (Tajima et al 1990;Guedel & Wentzel 1993).…”

Section: Introductionmentioning

confidence: 99%

Do solar decimetric spikes originate in coronal X-ray sources?

Battaglia¹,

Benz²

2009

A&A

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Context. In the standard solar flare scenario, a large number of particles are accelerated in the corona. Nonthermal electrons emit both X-rays and radio waves. Thus, correlated signatures of the acceleration process are predicted at both wavelengths, coinciding either close to the footpoints of a magnetic loop or near the coronal X-ray source. Aims. We attempt to study the spatial connection between coronal X-ray emission and decimetric radio spikes to determine the site and geometry of the acceleration process. Methods. The positions of radio-spike sources and coronal X-ray sources are determined and analyzed in a well-observed limb event. Radio spikes are identified in observations from the Phoenix-2 spectrometer. Data from the Nançay radioheliograph are used to determine the position of the radio spikes. RHESSI images in soft and hard X-ray wavelengths are used to determine the X-ray flare geometry. Those observations are complemented by images from GOES/SXI. Results. We find that the radio emission originates at altitudes much higher than the coronal X-ray source, having an offset from the coronal X-ray source amounting to 90 and to 113 and 131 from the two footpoints, averaged over time and frequency. Conclusions. Decimetric spikes do not originate from coronal X-ray flare sources contrary to previous expectations. However, the observations suggest a causal link between the coronal X-ray source, related to the major energy release site, and simultaneous activity in the higher corona.

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“…The observation of a 39.5 MHz high-frequency cutoff in the DAM was early evidence that Jupiter's cloud top magnetic field strength must be near 14 G, a fact later confirmed by Pioneer 10 (Acuna& Ness 1976; Smith, Davis, & Jones 1976). The extraordinary radiated power of the decametric emission, upward of 10 13 W, is explained by a maser-induced radiation process known as the electron cyclotron maser (Wu & Lee 1979;Melrose & Dulk 1982). An important feature of the DAM from the standpoint of particle acceleration processes is the fact that much of the emission is driven by Jupiter's innermost Galilean satellite, Io.…”

Section: Introductionmentioning

confidence: 99%

Jupiter Radio Bursts and Particle Acceleration

Desch¹

1994

International Astronomical Union Colloquium

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Particle acceleration processes are important in understanding many of the Jovian radio and plasma wave emissions. However, except for the high-energy electrons that generate synchrotron emission following inward diffusion from the outer magnetosphere, acceleration processes in Jupiter's magnetosphere and between Jupiter and Io are poorly understood. We discuss very recent observations from the Ulysses spacecraft of two new Jovian radio and plasma wave emissions in which particle acceleration processes are important and have been addressed directly by complementary investigations. First, radio bursts known as quasi-periodic bursts have been observed in close association with a population of highly energetic electrons. Second, a population of much lower energy (keV range) electrons on auroral field lines can be shown to be responsible for the first observation of a Jovian plasma wave emission known as auroral hiss.

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Electron-cyclotron masers as the source of certain solar and stellar radio bursts

Cited by 462 publications

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Phase connecting multi-epoch radio data for the ultracool dwarf TVLM 513-46546

Phase connecting multi-epoch radio data for the ultracool dwarf TVLM 513-46546

Do solar decimetric spikes originate in coronal X-ray sources?

Jupiter Radio Bursts and Particle Acceleration

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