Links to recent Solar Radio Science Highlights by Eduard Kontar

My many thanks to Dr. Eduard Kontar, University of Glasgow School of Physics and Astronomy,
and the Community of European Solar Radio Astronomers, for the following highlights.

About Dr. Eduard Kontar:
http://www.gla.ac.uk/schools/physics/staff/eduardkontar/

About CESRA:
http://www.astro.gla.ac.uk/users/eduard/cesra/?page_id=181

"The Community of European Solar Radio Astronomers (CESRA) is an informal organization of European
scientists to stimulate research of the outer solar atmosphere by means of radio waves and any
other suitable diagnostics."

"...CESRA publishes Highlights of Solar Radio Physics aka CESRA Nuggets approximately every two weeks at http://cesra.net. These short communications are written in the language accessible to a non-expert in the specific area and designed to keep solar and heliophysics communities informed and up-to-date about current research.
The highlights can be followed, discussed, commented and shared via
http://www.facebook.com/solarcesra/
http://twitter.com/CESRA_community    ..."

--------------------------------- 

An Extreme-ultraviolet Wave Generating Upward Secondary Waves in a
Streamer-like Solar Structure
by Ruisheng Zheng et al.*
http://cesra.net/?p=1925

Long-lasting injection of solar energetic electrons into the heliosphere
by N. Dresing et al.
http://cesra.net/?p=1916

Statistical Analysis of Solar Events Associated with storm sudden
commencements in the magnetosphere
by K. Bocchialini et al.*
http://www.astro.gla.ac.uk/users/eduard/cesra/?p=1895

Solar Radio Burst Associated with a Falling Bright EUV Blob
by M. Karlický et al.*
http://cesra.net/?p=1870

Properties of Decameter IIIb–III Pairs
by V. Melnik et al.*
http://cesra.net/?p=1875

Modeling of Solar Atmosphere Parameters Above Sunspots Using RATAN-600
Microwave Observations
by A.G. Stupishin et al.*
http://cesra.net/?p=1853

LOFAR observations of Fine Fundamental and Harmonic Structures in Solar
Radio Bursts
by Xingyao Chen et al*
http://cesra.net/?p=1848

Solar Type-IIIb Radio Bursts as Tracers for Electron Density
Fluctuations in the Corona
by V. Mugundhan et al.*
http://cesra.net/?p=1831

New evidence for a coronal mass ejection driven fast drifting type II
radio burst
by K. Ashnu et al.
http://cesra.net/?p=1818

Association of radio polar cap brightening with bright patches and
coronal holes
by C. L. Selhorst et al.*
http://cesra.net/?p=1807

Dressing the Coronal Magnetic Extrapolations of Active Regions with a
Parameterized Thermal Structure
by Gelu M. Nita et al.
http://cesra.net/?p=1798

Solar ALMA observations: constraining the chromosphere above sunspots
by M. Loukitcheva et al.*
http://cesra.net/?p=1777

Synergy of stochastic and systematic energization of plasmas during
turbulent reconnection
by Th. Pisokas, L. Vlahos and H. Isliker
http://cesra.net/?p=1773

The statistical relationship between global EUV waves and other solar
phenomena
by D. Long et al.*
http://cesra.net/?p=1763

Estimation of a CME magnetic field strength using observations of
gyrosynchrotron radiation
by E. P. Carley et al.*
http://cesra.net/?p=1701

Propagation and Interaction Properties of Successive Coronal Mass
Ejections in Relation to a Complex Type II Radio Burst
by Y. D. Liu et al.*
http://cesra.net/?p=1693

Observations of solar radio burst fine structures with LOFAR
by E. Kontar et al.*
http://cesra.net/?p=1675

VLA Measurements of Faraday Rotation through Coronal Mass Ejections
by Jason E. Kooi et al*
http://cesra.net/?p=1671

Solar Prominence Modelling at ALMA Wavelengths
by A. Rodger and N. Labrosse
http://cesra.net/?p=1647

Small electron acceleration episodes in the solar corona
by T. James et al.
http://cesra.net/?p=1635

Critical Fluctuations in Beam-Plasma Systems and Solar Type III Radio
Bursts
by G. Thejappa  and R. J. MacDowall
http://cesra.net/?p=1628

Acceleration and Storage of Energetic Electrons in Magnetic Loops in the
Course of Electric Current Oscillations
by V.V. Zaitsev and A.V. Stepanov
http://cesra.net/?p=1593

Flare SOL2012-07-06: on the origin of the circular polarization reversal
between 17 GHz and 34 GHz
by Altyntsev et al.*
http://cesra.net/?p=1578

Observations of a radio-quiet solar preflare
by A. Benz et al.*
http://cesra.net/?p=1562

Predicting Flares and Solar Energetic Particle Events: The FORSPEF Tool
by A. Anastasiadis et al.*
http://cesra.net/?p=1551

Exploring the potential of microwave diagnostics in SEP forecasting
by P. Zucca et al.
http://cesra.net/?p=1540

Solar plasma radio emission and inertial Alfven turbulence
by O. Lyubchyk et al.
http://cesra.net/?p=1525

EUV-invisible reservoir of solar energetic particles
by G. Fleishman et al..
http://cesra.net/?p=1499

Traveling Ionospheric Disturbances as Huge Natural Lenses: Solar Radio Emission Focusing Effect
by A. Koval et al.
http://cesra.net/?p=1480

Wavelet-based characterization of small-scale solar emission features at low radio frequencies
by A. Suresh et al.
http://cesra.net/?p=1473

Probing the Temperature Structure of the Solar Chromosphere with ALMA
by C. Alissandrakis et al.
http://cesra.net/?p=1457

Oscillation of solar radio emission at coronal acoustic cut-off frequency
by T. Zaqarashvili et al.
http://cesra.net/?p=1450

Siberian Radioheliograph: First Results
by S.V. Lesovoi et al.
http://cesra.net/?p=1426

The 30 cm solar radio flux: a new proxy for upper atmosphere specification
by Thierry Dudok de Wit and Sean Bruinsma
http://cesra.net/?p=1423

Particle acceleration and turbulence during a solar flare
by E.P. Kontar et al.
http://cesra.net/?p=1409

Solar wind density turbulence from 10 to 45 solar radii
by K. Sasikumar Raja et al.
http://cesra.net/?p=1385

Multi-Loop Structure of Nonthermal Microwave Sources in a Major Long-Duration Flare
by V. Grechnev et al.
http://cesra.net/?p=1375

Comparison of alternative zebra-structure models in solar radio emission
by G.P. Chernov et al.*
http://cesra.net/?p=1341

Microwave emission as a proxy of CME speed in ICME forecasting
by Carolina Salas Matamoros, Ludwig Klein and Gerard Trottet
http://cesra.net/?p=1336

The Brightness Temperature of the Quiet Solar Chromosphere at 2.6 mm
by Kazumasa Iwai et al
http://cesra.net/?p=1325

How Electron Beams Produce Continuous Coherent Plasma Emission
by H. Che, M. Goldstein, P. Diamond, and R. Sagdeev
http://cesra.net/?p=1310

Radio Diagnostics of Electron Acceleration Sites During the Eruption of a Flux Rope in the Solar Corona
by Eoin Carley et al.
http://cesra.net/?p=1188

Solar Science with the Atacama Large Millimeter/Submillimeter Array — A New View of Our Sun
by S. Wedemeyer
http://cesra.net/?p=1221

Quasi-periodic acceleration of electrons in the flare on 2012 July 19
by Jing Huang et al.
http://cesra.net/?p=1214

Large-scale simulations of Langmuir Wave Distributions Induced by Electron Beams
by H. Reid and E. Kontar
http://cesra.net/?p=1209

Full paper at:
"Langmuir Wave Electric Fields Induced by Electron Beams in the Heliosphere"
http://adsabs.harvard.edu/abs/2016arXiv161107901R
https://arxiv.org/pdf/1611.07901

Emission of radiation by plasmas with counter-streaming electron beams
by L. F. Ziebell et al.
http://cesra.net/?p=1200

Simultaneous near-Sun observations of a moving type IV radio burst
and the associated white-light CME
by K. Hariharan et al.
http://cesra.net/?p=1169

Observation of quasi-periodic solar radio bursts associated with propagating fast-mode waves
by C. R. Goddard et al.
http://cesra.net/?p=1159

Diagnosing the Source Region of a Solar Burst on 26 September 2011 by Using Microwave Type-III Pairs
by Tan B. L. et al.
http://cesra.net/?p=1138

Acceleration of electrons in the solar wind by Langmuir waves produced by a decay cascade
by Catherine Krafft and Alexander Volokitin
http://cesra.net/?p=1072

Source regions of the type II radio burst observed during a CME–CME interaction on 2013 May 22
by P. Mäkelä et al.
http://cesra.net/?p=1042

...

X9 flare coronal mass ejection at SOHO coronagraphs 170906

....
From SOHO coronagraph C2 and C3 data at:
https://sohodata.nascom.nasa.gov/cgi-bin/data_query
Many thanks
...

About the evolution of the Sun active regions

As the days go by, I frequently show details of active region magnetograms images and charts, and other data, for active regions I think may be suspect of initiating the radio events we study.

I started studying solar radio emission in 1966, I am not finished yet :)

The degree of activity frequently varies much from day to day and is a complex subject studied for many decades.

Lidia van Driel-Gesztelyi and Lucie May Green have published last month a "Living Review of Solar Physics" titled:

"Evolution of Active Regions" , 98 pages, including 17 pages of references, free to download at:

http://solarphysics.livingreviews.org/Articles/lrsp-2015-1/

http://solarphysics.livingreviews.org/Articles/lrsp-2015-1/download/lrsp-2015-1Color.pdf

Section 6 studies the case of AR 7978, "...subjected to the most comprehensive analysis of any AR..." as it evolved over a 6 month period.

Appendix A is a very good summary of Sunspot classifications, including the McIntosh and Hale methods.

I leave you repeating their quote from a poem by Laszlo Detre :

“  A Solar Physicist’s Lament  ....

It looks as if many a sunny day
Will pass along on its way
Before we solve it all...  "

My ignorance is vast
Have a wonderful day
Victor :)

--------------------------------
Solar Dynamics Observatory - Now and Daily - Images Movies
http://sdo.gsfc.nasa.gov/data/
Solar Type Examples
http://herrero-radio-astronomy.blogspot.com/2015/07/solar-type-examples.html
Comparison of Cycles 23 and 24 sunspot and coronal mass ejection numbers
http://3.bp.blogspot.com/-MxC1nf6CLuU/VcD2X3QT_kI/AAAAAAAALyg/n15qgyvN81g/s1600/W150804%2B50.png
http://sidc.oma.be/cactus/ CACTUS page
Introductory Radio Astronomy references
http://herrero-radio-astronomy.blogspot.com/2015/06/introductory-radio-astronomy-references.html?m=1
My recent event posts by month:
http://herrero-radio-astronomy.blogspot.com/2015/10/sun-earth-jupiter-20151001.html
http://herrero-radio-astronomy.blogspot.com/2015/09/sun-earth-jupiter-20150916.html
http://herrero-radio-astronomy.blogspot.com/2015/09/sun-earth-jupiter-2015-september.html
http://herrero-radio-astronomy.blogspot.com/2015/08/sun-earth-jupiter-2015-august.html
http://herrero-radio-astronomy.blogspot.com/2015/07/sun-earth-jupiter-2015-july.html
http://herrero-radio-astronomy.blogspot.com/2015/06/sun-earth-jupiter-2015-june.html
Links to earlier posts by month:
http://herrero-radio-astronomy.blogspot.com/2015/08/links-to-monthly-sun-earth-jupiter-posts.html?m=1
---------------------------------

Reference to a study of herringbones in Type II event on 2011 September 22 related to an X1.4 flare

With many thanks I refer to :

Carley Reid Vilmer Gallagher 2015, "Low frequency radio observations of bi-directional electron beams in the solar corona"

http://arxiv.org/abs/1508.01065

http://adsabs.harvard.edu/cgi-bin/bib_query?arXiv:1508.01065

66 references at:
http://adsabs.harvard.edu/cgi-bin/nph-ref_query?bibcode=2015A%26A...581A.100C&refs=REFERENCES&db_key=AST
......

LOFAR tied-array imaging and spectroscopy of solar S bursts

With many thanks I refer to Morosan et al. 2015

http://arxiv.org/abs/1507.07496

29 references at:
http://adsabs.harvard.edu/cgi-bin/nph-ref_query?bibcode=2015arXiv150707496M&refs=REFERENCES&db_key=PREhttp://adsabs.harvard.edu/cgi-bin/nph-ref_query?bibcode=2015arXiv150707496M&refs=REFERENCES&db_key=PRE

"Context. The Sun is an active source of radio emission that is often associated with energetic phenomena ranging from nanoflares to coronal mass ejections (CMEs). At low radio frequencies (<100 MHz), numerous millisecond duration radio bursts have been reported, such as radio spikes or solar S bursts (where S stands for short). To date, these have neither been studied extensively nor imaged because of the instrumental limitations of previous radio telescopes. Aims. Here, Low Frequency Array (LOFAR) observations were used to study the spectral and spatial characteristics of a multitude of S bursts, as well as their origin and possible emission mechanisms. Methods. We used 170 simultaneous tied-array beams for spectroscopy and imaging of S bursts. Since S bursts have short timescales and fine frequency structures, high cadence (~50 ms) tied-array images were used instead of standard interferometric imaging, that is currently limited to one image per second. Results. On 9 July 2013, over 3000 S bursts were observed over a time period of ~8 hours. S bursts were found to appear as groups of short-lived (<1 s) and narrow-bandwidth (~2.5 MHz) features, the majority drifting at ~3.5 MHz/s and a wide range of circular polarisation degrees (2-8 times more polarised than the accompanying Type III bursts). Extrapolation of the photospheric magnetic field using the potential field source surface (PFSS) model suggests that S bursts are associated with a trans-equatorial loop system that connects an active region in the southern hemisphere to a bipolar region of plage in the northern hemisphere. Conclusions. We have identified polarised, short-lived solar radio bursts that have never been imaged before. They are observed at a height and frequency range where plasma emission is the dominant emission mechanism, however they possess some of the characteristics of electron-cyclotron maser emission."

...

Diminishing solar activity may bring new Ice Age by 2030

"...The arrival of intense cold similar to the one that raged during the “Little Ice Age”, which froze the world during the 17th century and in the beginning of the 18th century, is expected in the years 2030—2040. These conclusions were presented by Professor V. Zharkova (Northumbria University) during the National Astronomy Meeting in Llandudno in Wales by the international group of scientists, which also includes Dr Helen Popova of the Skobeltsyn Institute of Nuclear Physics and of the Faculty of Physics of the Lomonosov Moscow State University, Professor Simon Shepherd of Bradford University and Dr Sergei Zharkov of Hull University..."

"...In the current study published in 3 peer-reviewed papers the researchers analysed a total background magnetic field from full disk magnetograms for three cycles of solar activity (21-23) by applying the so-called “principal component analysis”, which allows to reduce the data dimensionality and noise and to identify waves with the largest contribution to the observational data. This method can be compared with the decomposition of white light on the rainbow prism detecting the waves of different frequencies. As a result, the researchers developed a new method of analysis, which helped to uncover that the magnetic waves in the Sun are generated in pairs, with the main pair covering 40% of variance of the data (Zharkova et al, 2012, MNRAS). The principal component pair is responsible for the variations of a dipole field of the Sun, which is changing its polarity from pole to pole during 11-year solar activity..."

http://astronomynow.com/2015/07/17/diminishing-solar-activity-may-bring-new-ice-age-by-2030/

 

Royal Astronomical Society National Astronomy Meeting 2015 Llandudno Wales :

http://nam2015.org/

http://nam2015.org/index.php/science-programme/parallel-sessions/list/2

Solar Type Examples

Structure of solar radio noise 150 to 432 MHz - combined observations of 4 storms with the Nancay Radioheliograph and the Giant Meterwave Radio Telescope

With many thanks I refer to:

Mercier Subramanian Chambe Janardhan 2014

"The structure of solar radio noise storms"

http://arxiv.org/abs/1412.8189

http://adsabs.harvard.edu/cgi-bin/bib_query?arXiv:1412.8189

27 References at:
http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015A%26A...576A.136M&link_type=REFERENCES&db_key=AST&high= 

Abstract: "Context. The Nançay Radioheliograph (NRH) routinely produces snapshot images of the full sun (field of view ~3 R&sun;) at 6 or 10 frequencies between 150 and 450 MHz, with typical resolution 3 arcmin and time cadence 0.2 s. Combining visibilities from the NRH and from the Giant Meterwave Radio Telescope (GMRT) allows us to produce images of the sun at 236 or 327 MHz, with the same field as the NRH, a resolution as low as 20 arcsec, and a time cadence 2 s.

Aims: We seek to investigate the structure of noise storms (the most common non-thermal solar radio emission) which is yet poorly known. We focus on the relation of position and altitude of noise storms with the observing frequency and on the lower limit of their sizes.

Methods: We use an improved version of a previously used method for combining NRH and GMRT visibilities to get high-resolution composite images and to investigate the fine structure of noise storms. We also use the NRH data over several consecutive days around the common observation days to derive the altitude of storms at different frequencies.

Results: We present results for noise storms on four days. Noise storms consist of an extended halo and of one or several compact cores with relative intensity changing over a few seconds. We found that core sizes can be almost stable over one hour, with a minimum in the range 31-35 arcsec (less than previously reported). The heliocentric distances of noise storms are ~1.20 and 1.35 R&sun; at 432 and 150 MHz, respectively. Regions where storms originate are thus much denser than the ambient corona and their vertical extent is found to be less than expected from hydrostatic equilibrium.

Conclusions: The smallest observed sizes impose upper limits on broadening effects due to scattering on density inhomogeneities in the low and medium corona and constrain the level of density turbulence in the solar corona. It is possible that scatter broadening has been overestimated in the past, and that the observed sizes cannot only be attributed to scattering. The vertical structure of the noise storms is difficult to reconcile with the classical columnar model."

...

...

A wonderful video celebrating 5 years of the Solar Dynamics Observatory - from NASA Goddard Space Flight Center Media Studios

http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=11742

Dynamics of flares and fine structure of solar radio emission 30-7000 MHz

Dynamics of flares and fine structure of solar radio emission 30-7000 MHz

I refer to Gennady Chernov, Valery Fomichev, Baolin Tan, Yihua Yan, Chengming Tan, Qijun Fu, 2014 :

http://arxiv.org/abs/1409.0660

http://adsabs.harvard.edu/cgi-bin/bib_query?arXiv:1409.0660

36 references at:
http://adsabs.harvard.edu/cgi-bin/nph-ref_query?bibcode=2015SoPh..290...95C&amp;refs=REFERENCES&amp;db_key=AST

Abstract: "Radiobursts exhibiting fine structure observed over two years during the rising phase of Cycle 24 by the Chinese Solar Broadband Radio Spectrometer (SBRS/Huairou) in the range 1 - 7.6 GHz and the spectrograph IZMIRAN in the meter range (25 - 270 MHz) are analyzed. In five events the zebra structure, various fiber bursts, and fast pulsations were observed. These observations have great importance for testing different theoretical models of fine structure formation, as, for example, only for explaining the zebra structure more than ten mechanisms have been proposed. The events on 15 and 24 February 2011 are of the greatest interest. In the course of the flare on 15 February (which occurred close to the center of disk) the zebra structure was observed during three sequential flare brightenings. The polarization changed sign in the third. This behavior of polarization combined with images of the corresponding flare brightenings, obtained in extreme ultraviolet radiation by the Solar Dynamics Observatory (SDO/AIA, 171 Å), provides important clues. The polarization of radio emission in all three cases is related to the ordinary wave mode of radio emission. The zebra structure was present at frequencies 190 - 220 MHz in the Culgoora spectrum. The event on 24 February 2011 is remarkable, as the zebra structure at frequencies of 2.6 - 3.8 GHz was not polarized and it appeared during the magnetic reconnection observed by SDO/AIA 171 Å in this limb flare. In the event on 9 August 2011, for the first time, a superfine millisecond structure was registered simultaneously in the fast pulsations and the stripes of the zebra structure. In the event on 1 August 2010 after the zebra structure two families of fibers bursts with opposite frequency drifts were observed. On 19 April 2012 the fibers against the background of type III bursts were observed by IZMIRAN and Nançay spectrographs. In the band of 42 - 52 MHz a group of nine slowly drifting narrow-band (</˜ 1 MHz) fibers formed a unique type II burst. Almost all events in the microwave range contain superfine structure in the form of the millisecond spikes, whose emission should be considered primary. It is possible that each type of fine structure is excited by the same mechanism, and the broad variety of events observed is related to the dynamics of flare processes."

Sun Earth Jupiter 2014 September

Many thanks to: STEREO and WIND Teams, Taxpayers of France, French Air Force, Nancay Decametric Array Team at the Nancay Radio Astronomy Station of Paris Observatory, Prof. Dr. Kazumasa Imai Kochi National College of Technology Kochi Japan, Trinity College Dublin Ireland Astrophysics Group, United States NOAA SWPC, NASA SDO HMI Magnetograph Team, Lockheed Martin Solar Laboratory