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.

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A Case Study of Explosion a Single Solar Burst Type III and IV due to Active Region AR1890

International Letters of Chemistry Physics and Astronomy ◽

10.18052/www.scipress.com/ilcpa.38.171 ◽

2014 ◽

Vol 38 ◽

pp. 171-180 ◽

Cited By ~ 1

Author(s):

Zety Sharizat Hamidi ◽

M.B. Ibrahim ◽

N.N.M. Shariff ◽

C. Monstein

Keyword(s):

Active Region ◽

Solar Flare ◽

Comprehensive Description ◽

Type Iii ◽

Solar Burst ◽

Type Iv ◽

The Earth ◽

Using Data

Using 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 IV event due to active region AR1890. This eruption has started since 14:15 UT with a formation of type III solar burst. To investigate the importance of the role of type III solar burst can potentially form a type IV solar burst, the literature review of both bursts is outlined in detailed. The orientation and position of AR1890 make the explosion of a class C-solar flare is not directly to the Earth. Nevertheless, it is clear that the interactions of others sunspots such as AR1893,AR1895,AR1896, AR1897 and AR1898 should be studied in detail to understand what makes the type III burst formed before the type IV solar burst.

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Connection between Active region complexity and Solar Flare strength

Proceedings of the International Astronomical Union ◽

10.1017/s1743921318001977 ◽

2018 ◽

Vol 13 (S340) ◽

pp. 75-76

Author(s):

K. Amareswari ◽

Sreejith Padinhatteeri ◽

K. Sankarasubramanian

Keyword(s):

Active Region ◽

Magnetic Fields ◽

Solar Flare ◽

Solar Flares ◽

Active Regions ◽

Magnetic Topology ◽

Automated Algorithm ◽

Almost All ◽

Full Disk

AbstractHale (1908) discovered the existence of magnetic fields in sunspots, and since then a consensus has been reached that magnetic fields play an important role in various forms of solar activities, such as solar flares . Modified Mount-Wilson scheme is one of the methodology to classify active regions based on their complexity . As per this scheme, sunspots are classified as α, β, γ, and δ with the complexity of the magnetic topology increasing from α to δ. The δ sunspots are known to be highly flare-productive. An existing automated algorithm (SMART-DF) is modified and used to identify δ-spots for the existing full disk SOHO/MDI data. The automatically identified δ-spots is compared with the NOAA-SRS database and found to be reproducing almost all the identified δ-spots. In thisstudy, the connection between formation of δ-spot and flares is also carried out using GOES flare flux and NOAA-SRS sunspot classification.

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Electron Density and Drift Rate of Solar Burst Type II during 1st June 2015

International Letters of Chemistry Physics and Astronomy ◽

10.18052/www.scipress.com/ilcpa.63.49 ◽

2016 ◽

Vol 63 ◽

pp. 49-56

Author(s):

Zety Sharizat Hamidi ◽

M.O. Ali ◽

N.N.M. Shariff ◽

C. Monstein

Keyword(s):

Solar Corona ◽

Electron Density ◽

Drift Rate ◽

Early Stage ◽

Complex Structure ◽

Type Ii ◽

X Ray ◽

Solar Burst ◽

Fine Structures ◽

Using Data

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.

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Radio Measurements of Coronal Magnetic Fields

International Astronomical Union Colloquium ◽

10.1017/s0252921100024933 ◽

1994 ◽

Vol 144 ◽

pp. 21-28 ◽

Cited By ~ 4

Author(s):

G. B. Gelfreikh

Keyword(s):

Magnetic Field ◽

Magnetic Fields ◽

Solar Corona ◽

Active Regions ◽

High Sensitivity ◽

Coronal Magnetic Field ◽

Transverse Magnetic ◽

Radio Sources ◽

Radio Waves ◽

Solar Active Regions

AbstractA review of methods of measuring magnetic fields in the solar corona using spectral-polarization observations at microwaves with high spatial resolution is presented. The methods are based on the theory of thermal bremsstrahlung, thermal cyclotron emission, propagation of radio waves in quasi-transverse magnetic field and Faraday rotation of the plane of polarization. The most explicit program of measurements of magnetic fields in the atmosphere of solar active regions has been carried out using radio observations performed on the large reflector radio telescope of the Russian Academy of Sciences — RATAN-600. This proved possible due to good wavelength coverage, multichannel spectrographs observations and high sensitivity to polarization of the instrument. Besides direct measurements of the strength of the magnetic fields in some cases the peculiar parameters of radio sources, such as very steep spectra and high brightness temperatures provide some information on a very complicated local structure of the coronal magnetic field. Of special interest are the results found from combined RATAN-600 and large antennas of aperture synthesis (VLA and WSRT), the latter giving more detailed information on twodimensional structure of radio sources. The bulk of the data obtained allows us to investigate themagnetospheresof the solar active regions as the space in the solar corona where the structures and physical processes are controlled both by the photospheric/underphotospheric currents and surrounding “quiet” corona.

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Sensitivity of low-degree solar p modes to active and ephemeral regions: frequency shifts back to the Maunder minimum

Monthly Notices of the Royal Astronomical Society Letters ◽

10.1093/mnrasl/slz132 ◽

2019 ◽

Vol 489 (1) ◽

pp. L86-L90 ◽

Cited By ~ 1

Author(s):

William J Chaplin ◽

Rachel Howe ◽

Sarbani Basu ◽

Yvonne Elsworth ◽

Timothy W Milbourne ◽

...

Keyword(s):

Active Region ◽

Magnetic Fields ◽

Spatial Scales ◽

Active Regions ◽

Activity Cycle ◽

Maunder Minimum ◽

Field Frequency ◽

Frequency Shifts ◽

Near Surface ◽

Low Degree

ABSTRACT We explore the sensitivity of the frequencies of low-degree solar p modes to near-surface magnetic flux on different spatial scales and strengths, specifically to active regions with strong magnetic fields and ephemeral regions with weak magnetic fields. We also use model reconstructions from the literature to calculate average frequency offsets back to the end of the Maunder minimum. We find that the p-mode frequencies are at least 3 times less sensitive (at 95 per cent confidence) to the ephemeral-region field than they are to the active-region field. Frequency shifts between activity cycle minima and maxima are controlled predominantly by the change of active region flux. Frequency shifts at cycle minima (with respect to a magnetically quiet Sun) are determined largely by the ephemeral flux, and are estimated to have been $0.1\, \rm \mu Hz$ or less over the last few minima. We conclude that at epochs of cycle minimum, frequency shifts due to near-surface magnetic activity are negligible compared to the offsets between observed and model frequencies that arise from inaccurate modelling of the near-surface layers (the so-called surface term). The implication is that this will be the case for other Sun-like stars with similar activity, which has implications for asteroseismic modelling of stars.

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Statistical Properties of Magnetic Separators in Model Active Regions

Symposium - International Astronomical Union ◽

10.1017/s0074180900163454 ◽

2000 ◽

Vol 195 ◽

pp. 443-444

Author(s):

B. T. Welsch ◽

D. W. Longcope

Keyword(s):

Active Region ◽

Solar Corona ◽

Magnetic Reconnection ◽

First Principles ◽

Magnetic Charge ◽

Active Regions ◽

Heating Rates ◽

X Ray ◽

Field Lines ◽

Charge Topology

“Transient brightenings” (or “microflares”) regularly deposit 1027 ergs of energy in the solar corona, and account for perhaps 20% of the active corona's power (Shimizu 1995). We assume these events correspond to episodes of magnetic reconnection along magnetic separators in the solar corona. Using the techniques of magnetic charge topology, we model active region fields as arising from normally distributed collections of “magnetic charges”, point-like sources/sinks of flux (or field lines). Here, we present statistically determined separator (X-ray loop) lengths, derived from first principles. We are in the process of statistical calculations of heating rates due to reconnection events along many separators.

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The Reversed Polarity Structures of Chromospheric Magnetic Fields in Active Regions

International Astronomical Union Colloquium ◽

10.1017/s0252921100029286 ◽

1993 ◽

Vol 141 ◽

pp. 299-301

Author(s):

Wei Li ◽

Guoxiang Ai ◽

Hongqi Zhang ◽

Jimin Chen

Keyword(s):

Magnetic Field ◽

Magnetic Fields ◽

Solar Magnetic Field ◽

Active Regions ◽

Opposite Polarity ◽

Different Types ◽

Fine Structures ◽

Reversed Polarity

AbstractThe reversed polarity structures of chromospheric magnetic fields are magnetic gulfs and islands of opposite polarity relative to the underlying photospheric fields. In this paper data were analyzed from the Solar Magnetic Field Telescope of the Huairou Solar Observing Station (HSOS) in Beijing. From more than 300 pairs of photospheric magnetograms (in FeI λ5324.19 Å) and relevant chromospheric magnetograms (in Hβλ4861.34 Å), the reality of the reversed polarity structures is demonstrated. According to an analysis of the fine structures of the magnetic fields in the two layers of active regions, we found that there are probably four different types.

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