Efficiency of electron acceleration by shock waves in the solar corona according to observational data on the fine structure of type II radio bursts

1998 ◽  
Vol 41 (2) ◽  
pp. 107-114 ◽  
Author(s):  
V. V. Zaitsev ◽  
E. Y. Zlotnik ◽  
G. Mann ◽  
H. Aurass ◽  
A. Klassen
Keyword(s):  
Fine Structure ◽  
Shock Waves ◽  
Solar Corona ◽  
Observational Data ◽  
Electron Acceleration ◽  
Radio Bursts ◽  
Type Ii ◽  
Type Ii Radio Bursts

scholarly journals Observations of shock propagation through turbulent plasma in the solar corona

2021 ◽  
Author(s):  
Eoin Carley ◽  
Baptiste Cecconi ◽  
Hamish Reid ◽  
Carine Briand ◽  
K. Sasikumar Raja ◽  
...  
Keyword(s):  
Fine Structure ◽  
Solar Corona ◽  
Coronal Plasma ◽  
Shock Propagation ◽  
Radio Bursts ◽  
Type Ii ◽  
Developed Turbulence ◽  
Density Perturbations ◽  
Type Ii Radio Bursts ◽  
Size Scales

<p>Eruptive activity in the solar corona can often lead to the propagation of shockwaves. In the radio domain the primary signature of such shocks are type II radio bursts, observed in dynamic spectra as bands of emission slowly drifting towards lower frequencies over time. These radio bursts can sometimes have inhomogeneous and fragmented fine structure, but the cause of this fine structure is currently unclear. Here we observe several type II radio bursts on 2019-March-20th using the New Extension in Nancay Upgrading LOFAR (NenuFAR), a radio interferometer observing between 10-85 MHz. We show  that the distribution of size-scales of density perturbations associated with the fine structure of one type II follows a power law with a spectral index of -1.71, which closely matches the value of -5/3 expected of fully developed turbulence. We determine this turbulence to be upstream of the shock, in background coronal plasma at a heliocentric distance of ~2 R<sub>sun</sub>. The observed inertial size-scales of the turbulent density inhomogeneities range from ~62 Mm to ~209 km. This shows that type II fine structure and fragmentation can be due to shock propagation through an inhomogeneous and turbulent coronal plasma, and we discuss the implications of this on electron acceleration in the coronal shock.</p>

Fine structure of decametric type II radio bursts

2007 ◽  
Vol 33 (3) ◽  
pp. 192-202 ◽  
Author(s):  
G. P. Chernov ◽  
A. A. Stanislavsky ◽  
A. A. Konovalenko ◽  
E. P. Abranin ◽  
V. V. Dorovsky ◽  
...  
Keyword(s):  
Fine Structure ◽  
Radio Bursts ◽  
Type Ii ◽  
Type Ii Radio Bursts

scholarly journals Height of shock formation in the solar corona inferred from observations of type II radio bursts and coronal mass ejections

2013 ◽  
Vol 51 (11) ◽  
pp. 1981-1989 ◽  
Author(s):  
N. Gopalswamy ◽  
H. Xie ◽  
P. Mäkelä ◽  
S. Yashiro ◽  
S. Akiyama ◽  
...  
Keyword(s):  
Solar Corona ◽  
Coronal Mass Ejections ◽  
Shock Formation ◽  
Radio Bursts ◽  
Type Ii ◽  
Type Ii Radio Bursts

scholarly journals Radio Data and Computer Simulations for Shock Waves Generated by Solar Flares

1980 ◽  
Vol 91 ◽  
pp. 251-255
Author(s):  
Alan Maxwell ◽  
Murray Dryer
Keyword(s):  
Shock Waves ◽  
Solar Corona ◽  
Computer Simulations ◽  
Solar Flares ◽  
Solar Radio ◽  
Radio Bursts ◽  
Type Ii ◽  
Fast Mode ◽  
Solar Radio Bursts ◽  
Radio Data

Solar radio bursts of spectral type II provide a prime diagnostic for the passage of shock waves, generated by solar flares, through the solar corona. In this investigation we have compared radio data on the shocks with computer simulations for the propagation of fast-mode MHD shocks through the solar corona. The radio data were recorded at the Harvard Radio Astronomy Station, Fort Davis, Texas. The computer simulations were carried out at NOAA, Boulder, Colorado.

scholarly journals Electron Acceleration at Quasi-Parallel Shocks in The Solar Corona and Its Signature in Solar Type II Radio Bursts

1994 ◽  
Vol 142 ◽  
pp. 577-581
Author(s):  
G. Mann ◽  
H. Lühr
Keyword(s):  
Magnetic Field ◽  
Solar Corona ◽  
Radio Bursts ◽  
Type Ii ◽  
Radio Radiation ◽  
Earth’S Bow Shock ◽  
Type Ii Radio Bursts ◽  
Solar Type ◽  
Field Geometry ◽  
The Magnetic Field

AbstractRecently, strong large amplitude magnetic field structures (SLAMS) have been observed as a common phenomenon in the vicinity of the quasi-parallel region of Earth’s bow shock. A quasi-parallel shock transition can be considered as a patchwork of SLAMS. Using the data of the AMPTE/IRM magnetometer the properties of SLAMS are studied. Within SLAMS the magnetic field is strongly deformed and, thus, the magnetic field geometry is locally swung into a quasi-perpendicular regime. Therefore, electrons can locally be accelerated to high energies within SLAMS. Assuming that SLAMS also exist in the vicinity of supercritical, quasi-parallel shocks in the solar corona, they are able to generate radio radiation via the enhanced Langmuir turbulence excited by the accelerated electrons. Since SLAMS are connected with strong density enhancements, the aforementioned mechanism can explain the multiple-lane structure often occurred in solar Type II radio bursts.Subject headings: acceleration of particles — Earth — shock waves — Sun: corona — Sun: radio radiation

scholarly journals Coronal Shock Waves, EUV Waves, and Their Relation to CMEs. I. Reconciliation of “EIT Waves”, Type II Radio Bursts, and Leading Edges of CMEs

Solar Physics ◽  
2011 ◽  
Vol 273 (2) ◽  
pp. 433-460 ◽  
Author(s):  
V. V. Grechnev ◽  
A. M. Uralov ◽  
I. M. Chertok ◽  
I. V. Kuzmenko ◽  
A. N. Afanasyev ◽  
...  
Keyword(s):  
Shock Waves ◽  
Radio Bursts ◽  
Type Ii ◽  
Coronal Shock ◽  
Type Ii Radio Bursts ◽  
Leading Edges

scholarly journals Velocities of Shock Fronts in Solar Corona Generating Type II Radio Bursts at Metre Wavelengths

1962 ◽  
Vol 15 (1) ◽  
pp. 120
Author(s):  
M Krishnamurthi ◽  
G Sivarama Sastry ◽  
T Seshagiri Rao
Keyword(s):  
Shock Front ◽  
Solar Corona ◽  
Solar Flares ◽  
Radio Bursts ◽  
Type Ii ◽  
Plasma Oscillations ◽  
Slow Drift ◽  
Type Ii Radio Bursts ◽  
Shock Fronts ◽  
Comprehensive Study

At the time of intense solar flares, various types of enhanced radio emission from the Sun have been observed. Using such techniques as the swept frequency technique first developed by Wild and his associates, these enhanced emissions have been classified into five types. Of particular interest to radio astronomy at metre wavelengths is the slow drift type II bursts. A comprehensive study of these bursts has been made by Roberts (1959). It is now supposed that at the start of a flare an explosion occurs in the lower regions of the solar atmosphere ejecting a column of gas which travels radially outward from the region of the flare. This column of gas is bounded by a shock front which moves forward relative to this gas. This shock front is assumed to excite plasma oscillations in the solar corona giving rise to type II radiation. Velocities of these shock fronts have been determined by various workers.

Radio Evidence for Electron Acceleration by Transverse Shock Waves in Herringbone Type II Solar Bursts

1980 ◽  
Vol 4 (1) ◽  
pp. 53-55 ◽  
Author(s):  
R. T. Stewart ◽  
A. Magun
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Solar Corona ◽  
Direct Evidence ◽  
Electron Acceleration ◽  
Type Ii ◽  
Radio Observations ◽  
Type Iii ◽  
Solar Bursts ◽  
Herringbone Structure

Perhaps the most direct evidence to date for shock wave acceleration of electrons in the solar corona is provided by radio observations of Type II bursts containing herringbone structure (Roberts 1959). On spectral records the herringbones appear to resemble miniature forward and reverse drift Type III bursts extending above and below the Type II backbone.

scholarly journals Shock Waves and the Ejection of Matter from the Sun: Radio Evidence

1974 ◽  
Vol 57 ◽  
pp. 301-321
Author(s):  
D. J. McLean
Keyword(s):  
Shock Waves ◽  
Solar Corona ◽  
Recent Work ◽  
The Sun ◽  
Radio Bursts ◽  
Type Ii ◽  
Type Iv

The passage of shock waves and ejected matter through the solar corona can produce type II and type IV radio bursts. This paper reviews the observations of these types of bursts and their interpretation, with particular emphasis on recent work.

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