A statistical study of CMEs associated with metric type II bursts

2003 ◽  
Vol 30 (12) ◽  
Author(s):  
A. Lara ◽  
N. Gopalswamy ◽  
S. Nunes ◽  
G. Muñoz ◽  
S. Yashiro
Keyword(s):  
Statistical Study ◽  
Type Ii ◽  
Type Ii Bursts

scholarly journals Studies on Longer Wavelength Type II Radio Bursts Associated with Flares and CMEs during the Rise and Decay Phase of 23rd Solar Cycle

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
V. Vasanth ◽  
S. Umapathy
Keyword(s):  
Solar Cycle ◽  
Statistical Study ◽  
Decay Phase ◽  
Radio Bursts ◽  
Type Ii ◽  
23Rd Solar Cycle ◽  
Type Ii Radio Bursts ◽  
The Mean ◽  
Type Ii Bursts ◽  
Rise Phase

A statistical study on the properties of CMEs and flares associated with DH-type II bursts in the 23rd solar cycle during the period 1997–2008 is carried out. A sample of 229 events from our recent work is used for the present study (Vasanth and Umapathy, 2013). The collected events are divided into two groups as (i) solar cycle rise phase events and (ii) solar cycle decay phase events. The properties of CMEs in the two groups were compared and the results are presented. It is noted that there is no difference in the properties of type II burst like start frequency and end frequency between the solar cycle rise phase events and decay phase events. The mean CME speed of solar cycle decay phase events (1373 km s−1) is slightly higher than the solar cycle rise phase events (1058 km s−1). The mean CME acceleration of solar cycle decay phase events (−15.18 m s−2) is found to be higher than that of the solar cycle rise phase events (−1.32 m s−2). There exists good correlation between (i) CME speed and width and (ii) CME speed and acceleration for solar cycle decay phase events (R=0.79, R=-0.80) compared to solar cycle rise phase events (R=0.60, R=-0.57). These results indicate that the type II bursts parameters do not depend upon the time of appearance in the solar cycle.

scholarly journals The relation between the bolometric flux and the blackbody temperature at the peak of type II bursts from the Rapid Burster

1992 ◽  
Vol 256 (4) ◽  
pp. 624-630 ◽  
Author(s):  
L. M. Lubin ◽  
W. H. G. Lewin ◽  
T. Dotani ◽  
T. Oosterbroek ◽  
K. Mitsuda ◽  
...  
Keyword(s):  
Type Ii ◽  
Type Ii Bursts

scholarly journals EXPLORATION OF THE SOLAR DECAMETER RADIO EMISSION WITH THE UTR-2 RADIO TELESCOPE

2021 ◽  
Vol 26 (1) ◽  
pp. 74-89
Author(s):  
V. N Melnik ◽  
◽  
A. A. Konovalenko ◽  
V. V. Dorovskyy ◽  
A. Lecacheux ◽  
...  
Keyword(s):  
Radio Emission ◽  
Radio Telescope ◽  
Solar Radio Emission ◽  
The Sun ◽  
Type Ii ◽  
Time Frequency ◽  
Type Iii ◽  
Type Iv ◽  
Decameter Radio ◽  
Type Ii Bursts

Purpose: The overview of the scientifi c papers devoted to the study of the solar decameter radio emission with the world’s largest UTR-2 radio telescope (Ukraine) published for the last 50 years. Design/methodology/approach: The study and analysis of the scientifi c papers on both sporadic and quiet (thermal) radiation of the Sun recorded with the UTR-2 radio telescope at the decameter wavelength range. Findings: The most signifi cant observational and theoretical results of the solar radio emission studies obtained at the Institute of Radio Astronomy of the National Academy of Sciences of Ukraine for the last 50 years are given. Conclusions: For the fi rst time, at frequencies below 30 MHz, the Type II bursts, Type IV bursts, S-bursts, drift pairs and spikes have been recorded. The dependences of these bursts parameters on frequency within the frequency band of 9 to 30 MHz were obtained. The models of their generation and propagation were suggested. Moreover, for the fi rst time the fi ne time-frequency structures of the Type III bursts, Type II bursts, Type IV bursts, U- and J-bursts, S-bursts, and drift pairs have been observed due to the high sensitivity and high time-frequency resolutions of the UTR-2 radio telescope. The super-fi ne structure of Type II bursts with a “herringbone” structure was identifi ed, which has never been observed before. New types of bursts were discovered: “caterpillar” bursts, “dog-leg” bursts, Type III bursts with decay, Type III bursts with changing drift rate sign, Type III-like bursts, Jb- and Ub-bursts, etc. An interpretation of the unusually high drift rates and drift rates with alternating signs of the Type III-like bursts was suggested. Based on the dependence of spike durations on frequency, the coronal plasma temperature profi le at the heliocentric heights of 1.5–3RS was determined. Usage of the heliographic and interferometric methods gave the possibility to start studies of the spatial characteristics – sizes and locations of the bursts emission sources. Thus, it was shown that at the decameter band, the Type III burst durations were defi ned by the emission source linear sizes, whereas the spike durations were governed by the collision times in the source plasma. It was experimentally proved that the effective brightness temperatures of the sources of solar sporadic radio emission at the decameter band may reach values of 1014–1015 K. In addition, it was found that the radii of the quiet Sun at frequencies 20 and 25 MHz are close to the distances from the Sun at which the local plasma frequency is equal to the corresponding observed frequency of radio emission in the Baumbach–Allen model. Key words: UTR-2; Sun; decameter radio emission; radio bursts; corona

Localizing the Source of Type II Emission Around a CME with the Sun Radio Interferometer Space Experiment (SunRISE) and MHD Simulations

2021 ◽  
Author(s):  
Alexander Hegedus ◽  
Ward Manchester ◽  
Justin Kasper ◽  
Joseph Lazio ◽  
Andrew Romero-Wolf
Keyword(s):  
Data Processing ◽  
Low Frequency ◽  
Solar Energetic Particle ◽  
Radio Interferometer ◽  
Valuable Insight ◽  
Type Ii ◽  
Plasma Parameters ◽  
Low Frequencies ◽  
The Earth ◽  
Type Ii Bursts

<p>The Earth’s Ionosphere limits radio measurements on its surface, blocking out any radiation below 10 MHz. Valuable insight into many astrophysical processes could be gained by having a radio interferometer in space to image the low frequency window, which has never been achieved. One application for such a system is observing type II bursts that track solar energetic particle acceleration occurring at Coronal Mass Ejection (CME)-driven shocks. This is one of the primary science targets for SunRISE, a 6 CubeSat interferometer to circle the Earth in a GEO graveyard orbit. SunRISE is a NASA Heliophysics Mission of Opportunity that began Phase B (Formulation) in June 2020, and plans to launch for a 12-month mission in mid-2023. In this work we present an update to the data processing and science analysis pipeline for SunRISE and evaluate its performance in localizing type II bursts around a simulated CME.</p><p>To create realistic virtual type II input data, we employ a 2-temperature MHD simulation of the May 13th 2005 CME event, and superimpose realistic radio emission models on the CME-driven shock front, and propagate the signal through the simulated array. Data cuts based on different plasma parameter thresholds (e.g. de Hoffman-Teller velocity and angle between shock normal and the upstream magnetic field) are tested to get the best match to the true recorded emission.  This model type II emission is then fed to the SunRISE data processing pipeline to ensure that the array can localize the emission. We include realistic thermal noise dominated by the galactic background at these low frequencies, as well as new sources of phase noise from positional uncertainty of each spacecraft. We test simulated trajectories of SunRISE and image what the array recovers, comparing it to the virtual input, finding that SunRISE can resolve the source of type II emission to within its prescribed goal of 1/3 the CME width. This shows that SunRISE will significantly advance the scientific community’s understanding of type II burst generation, and consequently, acceleration of solar energetic particles at CMEs.  This unique combination of SunRISE observations and MHD recreations of space weather events will allow an unprecedented look into the plasma parameters important for these processes. </p>

scholarly journals GRO J1744-28 and the Rapid Burster; Bizarre Objects!

1998 ◽  
Vol 188 ◽  
pp. 111-111
Author(s):  
Walter H.G. Lewin
Keyword(s):  
Type Ii ◽  
Time Intervals ◽  
Periodic Oscillations ◽  
X Ray ◽  
Magnetic Dipole Field ◽  
Order Of Magnitude ◽  
Low Mass ◽  
Type Ii Bursts ◽  
The Difference ◽  
X Ray Binaries

The bursts from GRO J1744-28 are due to accretion instabilities as is the case for type II bursts in the Rapid Burster. Both sources are transient Low-Mass X-ray Binaries, and they both exhibit unusual quasi-periodic-oscillations in their persistent X-ray flux following several (not all) of the type II bursts. There are important differences too. GRO J1744-28 is an X-ray pulsar; the Rapid Burster is not. In addition, the pattern of bursts and the burst peak luminosities are very different for the two sources. Time intervals between the rapidly repetitive bursts in the Rapid Burster can be as short as 10 sec, in 1744-28 they are as short as 200 sec. The peak luminosities of the bursts from GRO J1744-28 can exceed the Eddington luminosity (for assumed isotropic emission) by one to two orders of magnitude. The QPO centroid frequencies (see above) differ by an order of magnitude (~0.04 Hz for the Rapid Burster, and 0.3 Hz for GRO J1744-28). The difference in behavior p obably lies in the difference in the magnetic dipole field strength of the accreting neutron stars (for GRO J1744-28 it is almost certainly much higher than for the Rapid Burster). It remains puzzling, why GRO J1744-28 and the Rapid Burster are the only known sources which exhibit rapidly repetitive type II bursts.

scholarly journals Polarization of Herringbone Structure in Type II Bursts

1980 ◽  
Vol 86 ◽  
pp. 241-245
Author(s):  
S. Suzuki ◽  
R. T. Stewart ◽  
A. Magun
Keyword(s):  
Type Ii ◽  
Unusual Structure ◽  
Type Ii Bursts ◽  
Herringbone Structure

Herringbone Type II bursts were first described by Roberts (1959). These bursts are distinguished by their unusual structure - rib-like features (herringbones) extending on either side of a Type II backbone.

scholarly journals Fragmented type II burst emission during CME liftoff

2008 ◽  
Vol 4 (S257) ◽  
pp. 357-359
Author(s):  
Silja Pohjolainen ◽  
Jens Pomoell ◽  
Rami Vainio
Keyword(s):  
Active Region ◽  
Dynamic Spectrum ◽  
Shock Acceleration ◽  
Type Ii ◽  
Know How ◽  
Loop Area ◽  
Mhd Simulations ◽  
Type Ii Bursts ◽  
Mass Ejection ◽  
Radio Event

AbstractWe have performed multiwavelength analysis on an event with a metric type II burst, which appeared first as fragmented emission lanes in the radio dynamic spectrum. The start frequency was unusually high. Since type II bursts are thought to be signatures of propagating shock waves, it is of interest to know how the shocks, and the type II bursts, are formed. This radio event was associated with a flare and a coronal mass ejection (CME), and we investigate their connection. Observations suggested that a propagating shock was formed due to the erupting structures, and the observed radio emission reflects the high densities in active region loops. We then utilised numerical MHD simulations, to study the shock structure induced by an erupting CME, in a model corona including dense loops. Our simulations show that the fragmented part of the type II burst can be formed when a coronal shock driven by a CME passes through a system of dense loops overlying an active region. To produce fragmented emission, the conditions for plasma emission have to be more favourable inside the loop than in the inter-loop area. The obvious hypothesis, consistent with our simulation model, is that the shock strength decreases significantly in the space between the denser loops. Outside the active region, the type II burst dies out when the changing geometry no longer favours the electron shock-acceleration.

scholarly journals On Split-Band Structure in Type II Radio Bursts from the Sun

1974 ◽  
Vol 57 ◽  
pp. 389-393 ◽  
Author(s):  
S. F. Smerd ◽  
K. V. Sheridan ◽  
R. T. Stewart
Keyword(s):  
Band Structure ◽  
The Sun ◽  
Radio Bursts ◽  
Type Ii ◽  
Band Splitting ◽  
Measured Amount ◽  
Type Ii Radio Bursts ◽  
Type Ii Bursts ◽  
Split Band

(Astrophys. Letters). The measured amount of band-splitting, Δf, in the spectra of nine harmonic type II bursts is illustrated in Figure 1. Here, as in previous, smaller samples (Roberts, 1959; Maxwell and Thompson, 1962; Weiss, 1965) Δf is found to increase with frequency, f.

Sign in / Sign up

Export Citation Format

Share Document