scholarly journals Inhibition of type III radio emissions due to the interaction between two electron beams: Observations and simulations

2014 ◽  
Vol 119 (4) ◽  
pp. 2365-2378 ◽  
Author(s):  
C. Briand ◽  
P. Henri ◽  
S. Hoang
Keyword(s):  
Electron Beams ◽  
Radio Emissions ◽  
Type Iii

scholarly journals The effects of density inhomogeneities on the radio wave emission in electron beam plasmas

2021 ◽  
Vol 87 (2) ◽  
Author(s):  
Xin Yao ◽  
Patricio A. Muñoz ◽  
Jörg Büchner ◽  
Xiaowei Zhou ◽  
Siming Liu
Keyword(s):  
Magnetic Reconnection ◽  
Radio Wave ◽  
Solar Flares ◽  
Electron Beams ◽  
Distribution Functions ◽  
Plasma Emission ◽  
Langmuir Waves ◽  
Radio Emissions ◽  
Density Inhomogeneities ◽  
Effects Of Density

Type III radio bursts are radio emissions associated with solar flares. They are considered to be caused by electron beams travelling from the solar corona to the solar wind. Magnetic reconnection is a possible accelerator of electron beams in the course of solar flares since it causes unstable distribution functions and density inhomogeneities (cavities). The properties of radio emission by electron beams in an inhomogeneous environment are still poorly understood. We capture the nonlinear kinetic plasma processes of the generation of beam-related radio emissions in inhomogeneous plasmas by utilizing fully kinetic particle-in-cell code numerical simulations. Our model takes into account initial electron velocity distribution functions (EVDFs) as they are supposed to be created by magnetic reconnection. We focus our analysis on low-density regions with strong magnetic fields. The assumed EVDFs allow two distinct mechanisms of radio wave emissions: plasma emission due to wave–wave interactions and so-called electron cyclotron maser emission (ECME) due to direct wave–particle interactions. We investigate the effects of density inhomogeneities on the conversion of free energy from the electron beams into the energy of electrostatic and electromagnetic waves via plasma emission and ECME, as well as the frequency shift of electron resonances caused by perpendicular gradients in the beam EVDFs. Our most important finding is that the number of harmonics of Langmuir waves increases due to the presence of density inhomogeneities. The additional harmonics of Langmuir waves are generated by a coalescence of beam-generated Langmuir waves and their harmonics.

scholarly journals Complex Type III-like radio emissions observed from 1 to 14 MHz

1999 ◽  
Vol 26 (3) ◽  
pp. 397-400 ◽  
Author(s):  
M. J. Reiner ◽  
M. L. Kaiser
Keyword(s):  
Complex Type ◽  
Radio Emissions ◽  
Type Iii

scholarly journals Numerical Simulation of Type III Bursts

1980 ◽  
Vol 86 ◽  
pp. 299-302
Author(s):  
T. Takakura
Keyword(s):  
Numerical Simulation ◽  
Analytical Method ◽  
Solar Radio ◽  
Plasma Waves ◽  
Radio Bursts ◽  
Emission Mechanism ◽  
Normal Type ◽  
Solar Radio Bursts ◽  
Radio Emissions ◽  
Type Iii

By the use of semi-analytical method, modeling of three kinds of type III solar radio bursts have been made. Many basic problems about the type III bursts and associated solar electrons have been solved showing some striking or unexpected results. If the fundamental radio emissions should be really observed as the normal type III bursts, the emission mechanism would not be the currently accepted one, i.e. the scattering of plasma waves by ions.

scholarly journals Observation of radio emissions from electron beams using an ice target

2019 ◽  
Vol 216 ◽  
pp. 02010
Author(s):  
Keiichi Mase ◽  
Daisuke Ikeda ◽  
Aya Ishihara ◽  
Hiroyuki Sagawa ◽  
Tatsunobu Shibata ◽  
...  
Keyword(s):  
Light Source ◽  
Electron Beams ◽  
High Energy ◽  
Neutrino Telescope ◽  
South Pole ◽  
The South ◽  
Telescope Array ◽  
Radio Emissions ◽  
Systematic Uncertainties ◽  
Radio Signals

To observe high energy cosmogenic neutrinos above 50 PeV, the large neutrino telescope ARA is being built at the South Pole. The ARA telescope detects neutrinos by observing radio signals by the Askaryan effect. We performed an experiment using 40 MeV electron beams of the Telescope Array Electron Light Source to verify the understanding of the Askaryan emission as well as the detector responses used in the ARA experiment. Clear coherent polarized radio signals were observed with and without an ice target. We found that the observed radio signals are consistent with simulation, showing that our understanding of the radio emissions and the detector responses are within the systematic uncertainties of the ARAcalTA experiment which is at the level of 30%.

Electron beams and radio waves of solar Type III bursts

1998 ◽  
Vol 103 (A8) ◽  
pp. 17223-17233 ◽  
Author(s):  
George A. Dulk ◽  
Yolande Leblanc ◽  
Peter A. Robinson ◽  
Jean-Louis Bougeret ◽  
Robert P. Lin
Keyword(s):  
Electron Beams ◽  
Radio Waves ◽  
Type Iii ◽  
Solar Type

Nonrelativistic electron beam expansion in the solar corona/wind  and their type III radio bursts observed with LOFAR

2021 ◽  
Author(s):  
Hamish Reid ◽  
Eduard Kontar
Keyword(s):  
Electron Beam ◽  
Energy Density ◽  
Solar Corona ◽  
Electron Beams ◽  
Low Frequency ◽  
High Energy ◽  
High Energy Density ◽  
Moderate Intensity ◽  
Radio Bursts ◽  
Type Iii

<div> <div><span>Solar type III radio bursts contain a wealth of information about the dynamics of near-relativistic electron beams in the solar corona and the inner heliosphere; this information is currently unobtainable through other means.  Whilst electron beams expand along their trajectory, the motion of different regions of an electron beam (front, middle, and back) had never been systematically analysed before.  Using LOw Frequency ARray (LOFAR) observations between 30-70 MHz of type III radio bursts, and kinetic simulations of electron beams producing derived type III radio brightness temperatures, we explored the expansion as electrons propagate away from the Sun.  From relatively moderate intensity type III bursts, we found mean electron beam speeds for the front, middle and back of 0.2, 0.17 and 0.15 c, respectively.  Simulations demonstrated that the electron beam energy density, controlled by the initial beam density and energy distribution have a significant effect on the beam speeds, with high energy density beams reaching front and back velocities of 0.7 and 0.35 c, respectively.  Both observations and simulations found that higher inferred velocities correlated with shorter FWHM durations of radio emission at individual frequencies.  Our radial predictions of electron beam speed and expansion can be tested by the upcoming in situ electron beam measurements made by Solar Orbiter and Parker Solar Probe.</span></div> </div>

Strongly structured radio emission observed by LOFAR on August 25, 2014

2020 ◽  
Author(s):  
Jasmina Magdalenic ◽  
Christophe Marque ◽  
Richard Fallows ◽  
Gottfried Mann ◽  
Christian Vocks ◽  
...  
Keyword(s):  
Radio Emission ◽  
Electron Beams ◽  
Low Frequency ◽  
Impulsive Phase ◽  
Continuum Emission ◽  
Type Ii ◽  
Type Iii ◽  
Type Iv ◽  
Fine Structures ◽  
Radio Event

<p>On August 25, 2014, NOAA AR 2146 produced the M2.0 class flare (peaked at 15:11 UT). The flare was associated with a halo CME and a radio event observed by LOFAR (the LOw-Frequency Array). The radio event consisted of a type II, type III and type IV radio emissions. In this study, we present LOFAR observations of the type II (radio signatures of shock waves) and type III bursts (radio signatures of fast electron beams propagating along open or quasi open field lines).  Both, the type II burst and type III bursts show strong fragmentation of the radio emission. Although fine structures of type II bursts were already reported, the richness of the fine structures observed in the studied event is unprecedented. We found type II fine structures morphologically very similar to the ones sometimes seen superposed on type IV continuum emission, and similar to simple narrowband super short structures (Magdalenic et al., 2006). The group of type III bursts was as usually, observed during the impulsive phase of the flare. The high frequency/time resolution LOFAR observations reveal that only few of the observed type III bursts have a smooth emission profile, and the majority of bursts is strongly fragmented. Surprisingly, fine structures of some type III bursts show similarities to the fine structures observed in the type II burst, but on a smaller frequency scale. Some of the type III bursts show a non-organized patchy structure which gives an indication on the possibly related turbulence processes. We show that these LOFAR observations bring completely new insight and pose a new challenge for the physics of the acceleration of electron beams and associated emission processes.</p>

scholarly journals Observations of Solar Type III Radio Bursts with the Nancay Radioheliograph

1980 ◽  
Vol 86 ◽  
pp. 235-240 ◽  
Author(s):  
M. Pick ◽  
A. Raoult ◽  
N. Vilmer
Keyword(s):  
Circular Polarization ◽  
Time Evolution ◽  
Electron Beams ◽  
Space Time ◽  
Radio Bursts ◽  
Temporal Characteristics ◽  
Type Iii ◽  
Solar Type ◽  
Space Time Evolution

Results on the space-time evolution of type III burst sources are summarized (Raoult and Pick, 1979) and observations on the temporal characteristics of the circular polarization are presented. It is shown that type III burst sources can be resolved into narrow components. Complex or very large sources may be explained by the occurrence of electron beams which propagate along different diverging paths. Propagating effects in a scattering corona are not required to explain the observations. The origin of the fundamental-harmonic pairs is briefly discussed.

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