Solar Bursts Research Articles

Electron Density and Drift Rate of Solar Burst Type II during 1<sup>st</sup> June 2015

This event allows us to investigate the electron density and drift rate of solar burst type II During 1st June 2015. It is believed that the plasma–magnetic field interactions in the solar corona can produce suprathermal electron populations over periods from tens of minutes to several hours, and the interactions of wave-particle and wave-wave lead to characteristic fine structures of the emission. An intense and broad solar radio burst type II was recorded by CALLISTO spectrometer from 25-80 MHz. Using data from a the Blein observatory, the complex structure of solar burst type III can also be found in the early stage of the formation of type II solar burst type event due to active region AR2358. The drift rate of solar burst type II exceeds 0.03 MHz/s with a density of electron in the solar corona. There are 18 CMEs occurring that day and the distributions of CME speed are between 200 ms-1 to 1100 ms-1 so that the average velocity of the CMEs that occur that day is 1025 m/s. This is one of the largest number of sunspots that have recorded in this year. However, all of these sunspots are quiet and stable and the solar activity remains low. Therefore, it can be observed that only B class of flare from the X-Ray Flux Data.

Electron Density and Drift Rate of Solar Burst Type II during 1<sup>st</sup> June 2015

This event allows us to investigate the electron density and drift rate of solar burst type II During 1stJune 2015. It is believed that the plasma–magnetic field interactions in the solar corona can produce suprathermal electron populations over periods from tens of minutes to several hours, and the interactions of wave-particle and wave-wave lead to characteristic fine structures of the emission. An intense and broad solar radio burst type II was recorded by CALLISTO spectrometer from 25-80 MHz. Using data from a the Blein observatory, the complex structure of solar burst type III can also be found in the early stage of the formation of type II solar burst type event due to active region AR2358. The drift rate of solar burst type II exceeds 0.03 MHz/s with a density of electron in the solar corona. There are 18 CMEs occurring that day and the distributions of CME speed are between 200 ms-1to 1100 ms-1so that the average velocity of the CMEs that occur that day is 1025 m/s. This is one of the largest number of sunspots that have recorded in this year. However, all of these sunspots are quiet and stable and the solar activity remains low. Therefore, it can be observed that only B class of flare from the X-Ray Flux Data.

Diamagnetic reduction in the magnetic field above a sunspot in the gamma-ray burst on July 14, 2000

Earlier, the authors proposed a model for describing the motion of trapped ions accelerated to energies of 10–100 MeV/nucleon in an electric field of 0.01–0.1 V/cm with a nonzero magnetic-field-aligned component in coronal solar loops with a characteristic size of ~100 000 km. The simulation results were used to interpret the properties of gamma-ray sources in a powerful solar burst that occurred on July 14, 2000. According to the proposed model, the gamma-ray source emitting lines with photon energies of 4.1–6.7 MeV was located above the sunspot and the source of the 2.223-MeV line coincided with the region of the observed drop-out of accelerated ions into dense layers of the solar atmosphere in the sunspot, where a short-term reduction in the photospheric magnetic field by about 100 G was simultaneously observed. An idea is stated and justified for the first time that the local reduction in the magnetic field in the sunspot is caused by the diamagnetic effect created by accelerated ions in the magnetic mirror of the coronal magnetic flux rope above the sunspot.

The New 30 THz Solar Telescope in São Paulo, Brazil

It has been found that solar bursts exhibit one unexpected spectral component with fluxes increasing with frequency in the sub-THz range, which is distinct from the well-known microwave emission that peaks at a few to some tens of GHz. This component has been found to extend into the THz range of frequencies by recent 30 THz solar flare observations of impulsive bursts with flux intensities considerably higher than fluxes at sub-THz and microwaves frequencies. High-cadence solar observations at 30 THz (continuum) are therefore an important tool for the study of active regions and flaring events. We report the recent installation of a new 30 THz solar telescope in Sao Paulo, located at the top of one of the University’s buildings. The instrument uses a Hale-type coelostat with two 20 cm diameter flat mirrors sending light to a 15 cm mirror Newtonian telescope. Radiation is directed to a microbolometer array camera that is kept at room temperature. Observations are usually obtained with \(5~\mbox{frames}\,\mbox{s}^{-1}\) cadence. One 60 mm refractor has been added to observe \(\mathrm{H}\upalpha\) images simultaneously. We describe our new telescopes and the new observatory examples of the first results obtained.

HIGH-FREQUENCY CUTOFF IN TYPE III BURSTS

In this article we report about a group of solar bursts with high-frequency cutoff, observed on 19 August of 2012 near 8:23 UT, simultaneously by three different radio telescopes: the Ukrainian decameter radio telescope (8-33 MHz), the French Nancay Decametric Array (10-70 MHz) and the Italian San Vito Solar Observatory of RSTN (25-180 MHz). Morphologically the bursts are very similar to the type III bursts. The solar activity is connected with the emergency of a new group of solar spots on the far side of the Sun with respect to observers on Earth. The solar bursts accompany many moderate flares over eastern limb. The refraction of the behind-limb radio bursts towards the Earth is favorable, if CMEs generate low-density cavities in solar corona

A SCENARIO FOR THE FINE STRUCTURES OF SOLAR TYPE IIIb RADIO BURSTS BASED ON ELECTRON CYCLOTRON MASER EMISSION

A scenario based on the electron cyclotron maser emission is proposed for the fine structures of solar radio emission in the present discussion. It is suggested that under certain conditions modulation of the ratio between the plasma frequency and electron gyro-frequency by ultra low frequency waves, which is a key parameter for excitation of the electron cyclotron maser instability, may lead to the intermittent emission of radio waves. As an example, the explanation of the observed fine-structure components in the solar type IIIb burst is discussed in detail. Three primary issues of the type IIIb bursts are addressed: 1) what is the physical mechanism that results in the intermittent emission elements that form a chain in the dynamic spectrum of type IIIb bursts, 2) what causes the split pair (or double stria) and the triple stria, 3) why in the events of fundamental-harmonic pair emission there is only IIIb-III, but IIIb-IIIb or III-IIIb cases are very rarely observed.

Bright 30 THz impulsive solar bursts

AbstractImpulsive 30 THz continuum bursts have been recently observed in solar flares, utilizing small telescopes with a unique and relatively simple optical setup concept. The most intense burst was observed together with a GOES X2 class event on 27 October 2014, also detected at two subterahertz (sub‐THz) frequencies, Reuven Ramaty High Energy Solar Spectroscopic Imager X‐rays and Solar Dynamics Observatory/Helioseismic and Magnetic Imager and EUV. It exhibits strikingly good correlation in time and in space with white‐light flare emission. It is likely that this association may prove to be very common. All three 30 THz events recently observed exhibited intense fluxes in the range of 104 solar flux units, considerably larger than those measured for the same events at microwave and submillimeter wavelengths. The 30 THz burst emission might be part of the same spectral burst component found at sub‐THz frequencies. The 30 THz solar bursts open a promising new window for the study of flares at their origin.

Preliminary Analysis on the Solar Burst Type III and the Effect of the Magnetic Reconnection

From the data from a BLEIN Callisto site, we aim to provide a comprehensive description of the synopsis formation and dynamics of a a single solar burst type III and magnetic reconnection effect. The data above is the solar radio burst type iii occurred on 10th September 2005 between 05:44 UT till 06:00 UT.This eruption has started since 5:55 UT with a formation of type III solar burst. The wave emission process of solar radio burst type III from magnetic reconnection region in a solar flare were investigated by using a two-dimensional, that are electromagnetic and relativistic particle-in-cell code. The solar radio burst type III initially impose into two plasma populations : background dense plasma and hot electrons that can be generated by the magnetic reconnection process in a solar flare. The conversion of the energy stored in the magnetic field by a process called the magnetic reconnection released the energy in the solar flares and related phenomena. By the launching the e-CALLISTO network, its prove the existence of the magnetic reconnection on the surface of the sun in radio region.

Investigation of Coronal Mass Ejections Related to Solar Flare Event and the Formation of the Small Geomagnetic Storm

This paper is highlighted on the duration of time for the Coronal Mass Ejections (CMEs) to occur related to solar flare event and the class of solar burst type III that present within the two phenomenon. It is important to understand the evaluations of solar flare until CMEs mean to be appearing and know the basic characterization of solar radio burst type III. It can be observed that CME is even larger than the sun itself. At certain period of time, when the Sun launches billons tones of electrically conducting gas plasma into the space at millions of miles per hours it is assigned that CMEs begin to launch. The data on 23rd of April was selected whereby; solar radio burst type 3 was detected (about 17:36 UT – 17:44 UT). At 17:40 solar flare with a radio burst and CMEs were produced by the sun. Associated with this event, current condition of solar wind speed is 359.5 km/sec with density of 6.0 protons/ and sunspot number are 118. Those at the high latitude have a chance of aurora due to the small geomagnetic storm.

Preliminary Analysis on the Solar Burst Type III and the Effect of the Magnetic Reconnection

From the data from a BLEIN Callisto site, we aim to provide a comprehensive description of the synopsis formation and dynamics of a a single solar burst type III and magnetic reconnection effect. The data above is the solar radio burst type iii occurred on 10th September 2005 between 05:44 UT till 06:00 UT.This eruption has started since 5:55 UT with a formation of type III solar burst. The wave emission process of solar radio burst type III from magnetic reconnection region in a solar flare were investigated by using a two-dimensional, that are electromagnetic and relativistic particle-in-cell code. The solar radio burst type III initially impose into two plasma populations : background dense plasma and hot electrons that can be generated by the magnetic reconnection process in a solar flare. The conversion of the energy stored in the magnetic field by a process called the magnetic reconnection released the energy in the solar flares and related phenomena. By the launching the e-CALLISTO network, its prove the existence of the magnetic reconnection on the surface of the sun in radio region.

Investigation of Coronal Mass Ejections Related to Solar Flare Event and the Formation of the Small Geomagnetic Storm

This paper is highlighted on the duration of time for the Coronal Mass Ejections (CMEs) to occur related to solar flare event and the class of solar burst type III that present within the two phenomenon. It is important to understand the evaluations of solar flare until CMEs mean to be appearing and know the basic characterization of solar radio burst type III. It can be observed that CME is even larger than the sun itself. At certain period of time, when the Sun launches billons tones of electrically conducting gas plasma into the space at millions of miles per hours it is assigned that CMEs begin to launch. The data on 23rd of April was selected whereby; solar radio burst type 3 was detected (about 17:36 UT – 17:44 UT). At 17:40 solar flare with a radio burst and CMEs were produced by the sun. Associated with this event, current condition of solar wind speed is 359.5 km/sec with density of 6.0 protons/ and sunspot number are 118. Those at the high latitude have a chance of aurora due to the small geomagnetic storm.

The Evolution of Unstable 'Beta-Gamma' Magnetic Fields of Active Region AR 2222

This event allows us to investigate how plasma–magnetic field interactions in the solar corona can produce suprathermal electron populations over periods from tens of minutes to several hours, and the interactions of wave-particle and wave-wave lead to characteristic fine structures of the emission. An intense and broad solar radio burst type IV was recorded by CALLISTO spectrometer from 240-360 MHz. Using data from a the KRIM observatory, we aim to provide a comprehensive description of the synopsis formation and dynamics of a a single solar burst type IV event due to active region AR2222. For five minutes, the event exhibited strong pulsations on various time scales and “broad patterns” with a formation of a group type III solar burst. AR 2222 remained the most active region, producing a number of minor C-Class solar flares. The speed of the solar wind also exceeds 370.8 km/second with 10.2 g/cm3 density of proton in the solar corona. The radio flux also shows 171 SFU. Besides, there are 3 active regions, AR2217, AR2219 and AR2222 potentially pose a threat for M-class solar flares. Active region AR2222 have unstable 'beta-gamma' magnetic fields that harbor energy for M-class flares. As a conclusion, we believed that Sun’s activities more active in order to achieve solar maximum cycle at the end of 2014.

Investigation of Drift Rate of Solar Radio Burst Type II due to Coronal Mass Ejections Phenomenon

The formation of detected solar radio burst type II occurred was captured using Compound Astronomical Low Cost Frequency Spectrometer Transportable Observatory (CALLISTO) system which gives a better resolution of a wonderful image than other countries. The phenomenon was found on 2nd November 2014 at 09:39 [UT] in Switzerland. CALLISTO spectrometer device detects and traces a Coronal Mass Ejections (CMEs) phenomenon that causes the occurrence of the solar burst type II. As it happened, the drift rate of the solar radio burst Type II is calculated and discussed in details. Plasma frequency (fp), Langmuir waves and type II radiation relates each other in the establishment of this phenomenon. This paper presents a study of drift rate selected event of solar radio burst type II based on CMEs. The drift rate at this moment was about 3.2 MHz/s which has low drift rate thus the velocity OF THE CMEs was just about 695 km/s shown from NOAA.

The Evolution of Unstable 'Beta-Gamma' Magnetic Fields of Active Region AR 2222

This event allows us to investigate how plasma–magnetic field interactions in the solar corona can produce suprathermal electron populations over periods from tens of minutes to several hours, and the interactions of wave-particle and wave-wave lead to characteristic fine structures of the emission. An intense and broad solar radio burst type IV was recorded by CALLISTO spectrometer from 240-360 MHz. Using data from a the KRIM observatory, we aim to provide a comprehensive description of the synopsis formation and dynamics of a a single solar burst type IV event due to active region AR2222. For five minutes, the event exhibited strong pulsations on various time scales and “broad patterns” with a formation of a group type III solar burst. AR 2222 remained the most active region, producing a number of minor C-Class solar flares. The speed of the solar wind also exceeds 370.8 km/second with 10.2 g/cm3 density of proton in the solar corona. The radio flux also shows 171 SFU. Besides, there are 3 active regions, AR2217, AR2219 and AR2222 potentially pose a threat for M-class solar flares. Active region AR2222 have unstable 'beta-gamma' magnetic fields that harbor energy for M-class flares. As a conclusion, we believed that Sun’s activities more active in order to achieve solar maximum cycle at the end of 2014.

Investigation of Drift Rate of Solar Radio Burst Type II due to Coronal Mass Ejections Phenomenon

The formation of detected solar radio burst type II occurred was captured using Compound Astronomical Low Cost Frequency Spectrometer Transportable Observatory (CALLISTO) system which gives a better resolution of a wonderful image than other countries. The phenomenon was found on 2nd November 2014 at 09:39 [UT] in Switzerland. CALLISTO spectrometer device detects and traces a Coronal Mass Ejections (CMEs) phenomenon that causes the occurrence of the solar burst type II. As it happened, the drift rate of the solar radio burst Type II is calculated and discussed in details. Plasma frequency (fp), Langmuir waves and type II radiation relates each other in the establishment of this phenomenon. This paper presents a study of drift rate selected event of solar radio burst type II based on CMEs. The drift rate at this moment was about 3.2 MHz/s which has low drift rate thus the velocity OF THE CMEs was just about 695 km/s shown from NOAA.

An Analysis of Eruption of the Sun Detected by Solar Radio Burst Type I

Type I solar burst were identified based on data recorded by CALLISTO BLEIN, Switzerland in the period of 17th of January, 2011. Solar Radio Burst Type I is one of the main type of solar burst which is believed to provide a diagnostic of electron acceleration in the corona. This noise storm burst is associated with emerging and growing active regions and last from hours to days. It can be observed that solar radio burst type I is formed within four minutes, although the number of sunspots is just 15. The results of the recent time indicate that Sunspot group 1147 has been mostly quiet since it rounded the eastern limb, but previous week's far side activity shows it is capable of significant eruptions. In 2011, only one day has been detected with spotless day, which means that it is about 7% of overall cases. Probabilities for significant disturbances in Earth's magnetic field are given for three activity levels: active, minor storm, severe storm. From the current conditions in the space weather website on 16th January 2011 that is the first event was shown that the solar wind occurred with a speed of 433.2 km/second while its density about 3.2 protons/cm3. Besides the solar wind, X-ray solar flare with 6 hours maximum: B1 at 1846 UT and 24 hours: B2 at 1544 UT were detected. While type I seem to be an indicator of pre-solar flare and CMEs, on the observational analysis, we could not directly confirmed that this is the only possibility, and we need to consider other processes to explain in detailed the injection, energy loss and the mechanism of the acceleration of the particles. We could conclude one active region will not produce a huge explosion of solar phenomena.

An Analysis of Eruption of the Sun Detected by Solar Radio Burst Type I

Type I solar burst were identified based on data recorded by CALLISTO BLEIN, Switzerland in the period of 17th of January, 2011. Solar Radio Burst Type I is one of the main type of solar burst which is believed to provide a diagnostic of electron acceleration in the corona. This noise storm burst is associated with emerging and growing active regions and last from hours to days. It can be observed that solar radio burst type I is formed within four minutes, although the number of sunspots is just 15. The results of the recent time indicate that Sunspot group 1147 has been mostly quiet since it rounded the eastern limb, but previous week's far side activity shows it is capable of significant eruptions. In 2011, only one day has been detected with spotless day, which means that it is about 7% of overall cases. Probabilities for significant disturbances in Earth's magnetic field are given for three activity levels: active, minor storm, severe storm. From the current conditions in the space weather website on 16th January 2011 that is the first event was shown that the solar wind occurred with a speed of 433.2 km/second while its density about 3.2 protons/cm3. Besides the solar wind, X-ray solar flare with 6 hours maximum: B1 at 1846 UT and 24 hours: B2 at 1544 UT were detected. While type I seem to be an indicator of pre-solar flare and CMEs, on the observational analysis, we could not directly confirmed that this is the only possibility, and we need to consider other processes to explain in detailed the injection, energy loss and the mechanism of the acceleration of the particles. We could conclude one active region will not produce a huge explosion of solar phenomena.

Analysis of Chains of Metric Solar Type I Bursts

Type I radio noise storms are believed to provide a diagnostic of electron acceleration in the corona. Most type I bursts appear in chains of five or more individual bursts. An analysis of the chain properties may indicate electron density, height of emission source, and magnetic-field intensity. We studied 255 chains of solar type I solar bursts recorded by the Compact Astronomical Low-cost Low-frequency Instrument for Spectroscopy and Transportable Observatory (CALLISTO-BLEN) spectrograph from 30 July to 9 August 2011 in the frequency range 170 – 870 MHz. Based on the morphological characteristics identified in the dynamic spectra, we determined the physical parameters for the events. The source electron density was found to be in the range 0.5 – 1.6×109 cm−3, the radial velocity of the emitting plasma varied from −1600 – 1500 km s−1, the magnetic-field strength was in the range 2.2 – 3.3 G, and the height of the source ranged from 0.95 to 1.15 solar radii. The results are consistent with previously reported values.

Visibility of Type III burst source location as inferred from stereoscopic space observations

Abstract. We study solar Type III radio bursts simultaneously observed by RPWS/Cassini, URAP/Ulysses and WAVES/Wind experiments. The observations allows us to cover a large frequency bandwidth from 16 MHz down to a few kHz. We consider the onset time of each burst, and estimate the corresponding intensity level. Also we measure the Langmuir frequency as observed on the dynamic spectra recorded by the Ulysses spacecraft. The distances of Wind, Ulysses and Cassini spacecraft, with regard to the Sun, were in the order of 1 AU, 2.4 AU and 4.5 AU, respectively. The spacecraft trajectories were localized in the ecliptic plane in the case of Wind and Cassini, and for Ulysses in the southern hemisphere (i.e. heliocentric latitude higher than −50°). Despite the different locations, the spectral patterns of the selected solar bursts are found to be similar between 10 MHz and 2 MHz but unalike at lower frequency. We discuss the variation of the intensity level as recorded by the three spacecraft. We show that the reception system of each experiment affected the way the Type III burst intensity is measured. Also we attempt to estimate the electron beam along the interplanetary magnetic field where the trajectory is an Archimedean spiral. This leads us to infer on the visibility of the source location with regard to the spacecraft position.

Solar Type II Radio Bursts Recorded by the Compound Astronomical Low-Frequency Low-Cost Instrument for Spectroscopy in Transportable Observatories in Brazil

It is well established that solar Type-II radio bursts are signatures of magnetohydrodynamical (MHD) shock waves propagating outward through the solar corona. Nevertheless, there are long-standing controversies about how these shocks are formed; solar flares and the coronal mass ejections (CMEs) are considered to be the most likely drivers. We present the results of the analysis of four solar Type-II bursts recorded between 20 January 2010 and 17 November 2011 by the Compound Astronomical Low-frequency Low-cost Instrument for Spectroscopy in Transportable Observatories (CALLISTO-BR) (in Brazil), which operates in the frequency range of 45 – 870 MHz. For all four solar Type-II radio bursts, which consisted of one event without band splitting and three split-band variants, the outcomes are consistent with those reported in the literature. All four Type-II radio bursts were accompanied by both solar flares and CMEs, which are associated with the impulsive phase of the flares and, very likely, with the acceleration phase of the CMEs.