Spatial analysis of solar type III events associated with narrow band spikes at metric wavelengths

Paesold, G.; Benz, A. O.; Klein, K.-L.; Vilmer, Nicole

doi:10.1051/0004-6361:20010358

Cited by 69 publications

(51 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Benz et al (1996) have shown that narrowband metric spikes in general correlate with type III bursts starting at slightly lower frequencies. The metric spikes have been found by Paesold et al (2001) to be located generally on the extension of type III trajectories and suggest a model of energy release taking place in or close to the spike sources. Modeling coronal densities (Paesold et al 2001) and spatially resolved observations of metric spike events (Krucker et al 1995(Krucker et al , 1997 put the sources at altitudes of 2×10 10 cm and more.…”

Section: Introductionmentioning

confidence: 86%

Location of narrowband spikes in solar flares

Benz

Saint-Hilaire²,

Vilmer³

2002

A&A

Self Cite

View full text Add to dashboard Cite

Abstract. Narrowband spikes of the decimeter type have been identified in dynamic spectrograms of Phoenix-2 of ETH Zurich and located in position with the Nançay Radioheliograph at the same frequency. The spike positions have been compared with the location of hard X-ray emission and the thermal flare plasma in soft X-rays and EUV lines. The decimetric spikes are found to be single sources located some 20 to 400 away from the flare site in hard or soft X-rays. In most cases there is no bright footpoint nearby. In at least two cases the spikes are near loop tops. These observations do not confirm the widely held view that the spike emission is produced by some loss-cone instability masering near the footpoints of flare loops. On the other hand, the large distance to the flare sites and the fact that these spikes are all observed in the flare decay phase make the analyzed spike sources questionable sites for the main flare electron acceleration. They possibly indicate coronal post-flare acceleration sites.

show abstract

Section: Introductionmentioning

confidence: 86%

Location of narrowband spikes in solar flares

Benz

Saint-Hilaire²,

Vilmer³

2002

A&A

Self Cite

View full text Add to dashboard Cite

show abstract

“…At frequencies above 270 MHz (e.g., 327 MHz in Fig. 1a), the time profile at 1 s resolution shows no evidence for individual type III bursts, but resembles decimetric broadband emission and spikes which are often seen above the high frequency limit of type III bursts (e.g., Paesold et al 2001, and references therein). Like in the type III emission at 164 MHz, the successive brightening at two positions is also seen in the 1D brightness at 327 MHz.…”

Section: Observationsmentioning

confidence: 94%

Coronal phenomena at the release of solar energetic electron events

Klein¹,

Krucker²,

Trottet³

et al. 2005

A&A

Self Cite

View full text Add to dashboard Cite

Abstract. We investigate dynamical processes in the solar corona at the release of electrons (∼30−500 keV) detected by the Wind/3DP experiment, with the aim to clarify the relationship between coronal acceleration and the escape of electrons to interplanetary space. Energetic electrons and plasma in the corona are traced using radio, EUV and X-ray observations. 40 events were identified where the release time of the electrons could be determined within an uncertainty of a few minutes and occurred during the observing hours of the Nançay Radioheliograph. All were accompanied by decametric-to-kilometric type III bursts (Wind/WAVES), and 30 by metric radio emission in the western hemisphere. The main findings from these 30 events are: (i) Electrons detected at Wind are released at the time of distinct episodes of electron acceleration in the corona signalled by radio emission. The release may occur at the start of the radio event or up to an hour later. (ii) The most conspicuous examples of delayed electron release occur in events associated with complex, long lasting (>10 min, up to seveal hours) radio emission. Radio observations suggest that in these cases the earlier accelerated electrons remain confined in the corona or are injected into flux tubes which are not connected to the spacecraft. (iii) Type II bursts revealing shock waves in the corona accompany about a third of the events. But the shock waves occur in general together with type IV radio signatures due to long lasting acceleration not related to the shock. With a few exceptions these type IV emissions have a clearer timing relationship with the electron release to space than the type II bursts. We conclude that the combination of time-extended acceleration at heights 0.5 R above the photosphere with the injection of electrons into a variety of closed and open magnetic field structures explains the broad variety of timing shown by the radio observations and the in situ measurements.

show abstract

“…The coronal conditions are described here via an isothermal atmosphere with Maxwellian distributions at T e = T i = 2 MK, and the number density varies according to the 4 Â Baumbach-Allen model [Baumbach, 1937;Allen, 1947] to represent an active region in the corona [Hughes and Harkness, 1963;Benz et al, 1983;Paesold et al, 2001] The source region is a conical frustum, which subtends a half angle q b at the Sun and has length l along its axis and radial distance d from the Sun. Within the source, the dynamics of beam, Langmuir waves and ion-sound waves are simulated in one dimension along the axis of the conical frustum, but radiation is simulated in three dimensions.…”

Section: Simulation Parametersmentioning

confidence: 99%

Simulations of coronal type III solar radio bursts: 2. Dynamic spectrum for typical parameters

Cairns

Robinson

2008

J. Geophys. Res.

View full text Add to dashboard Cite

[1] Predictions are presented for the dynamic spectrum of a coronal type III burst observed at Earth, using a newly developed simulation model and employing realistic electron release and coronal parameters. The spectrum is studied in detail in association with the dynamics of beam and waves in the source. The frequency drift rate, radio flux, brightness temperature, and temporal profile of the type III burst agree semiquantitatively with typical observations. The simulation model is thus viable. Because of strong freefree absorption and scattering-induced damping, the flux of f p emission is significantly lower than that of 2f p emission and is below the lower thresholds of typical radio instruments. Moreover, the f p emission terminates at frequencies higher than the minimum simulated, and the 2f p emission appears to terminate at higher coronal altitudes that are not simulated because of computational limitations. Further simulations indicate that F-H pairs may exist under favorable conditions (e.g., generally, lower levels and larger length scales of the density fluctuations).Citation: Li, B., I. H. Cairns, and P. A. Robinson (2008), Simulations of coronal type III solar radio bursts: 2. Dynamic spectrum for typical parameters,

show abstract

Spatial analysis of solar type III events associated with narrow band spikes at metric wavelengths

Cited by 69 publications

References 22 publications

Location of narrowband spikes in solar flares

Location of narrowband spikes in solar flares

Coronal phenomena at the release of solar energetic electron events

Simulations of coronal type III solar radio bursts: 2. Dynamic spectrum for typical parameters

Contact Info

Product

Resources

About