scholarly journals Short-Term Correlations of Decameter Radio Emission from Jupiter and Solar Activity.

1966 ◽  
Vol 71 ◽  
pp. 179
Author(s):  
Ch. V. Sastry
Keyword(s):  
Solar Activity ◽  
Radio Emission ◽  
Short Term ◽  
Decameter Radio

scholarly journals Radio Emission of Venus at 3 cm and the Solar Activity

Nature ◽  
1966 ◽  
Vol 211 (5045) ◽  
pp. 176-176 ◽  
Author(s):  
V. LETFUS
Keyword(s):  
Solar Activity ◽  
Radio Emission

Decameter radio emission of the Sun

2010 ◽  
Author(s):  
V. N. Melnik ◽  
A. A. Konovalenko ◽  
V. V. Dorovskyy ◽  
E. P. Abranin ◽  
H. Rucker ◽  
...  
Keyword(s):  
Radio Emission ◽  
The Sun ◽  
Decameter Radio

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

Numerical Short-Term Solar Activity Forecasting

2017 ◽  
Vol 13 (S335) ◽  
pp. 243-249 ◽  
Author(s):  
Huaning Wang ◽  
Yihua Yan ◽  
Han He ◽  
Xin Huang ◽  
Xinghua Dai ◽  
...  
Keyword(s):  
Solar Activity ◽  
Magnetic Fields ◽  
Solar Atmosphere ◽  
Magnetic Energy ◽  
Three Dimensional ◽  
Active Regions ◽  
Short Term ◽  
Solar Active Regions ◽  
Solar Eruptions ◽  
Dimensional Reconstruction

AbstractIt is well known that the energy for solar eruptions comes from magnetic fields in solar active regions. Magnetic energy storage and dissipation are regarded as important physical processes in the solar corona. With incomplete theoretical modeling for eruptions in the solar atmosphere, activity forecasting is mainly supported with statistical models. Solar observations with high temporal and spatial resolution continuously from space well describe the evolution of activities in the solar atmosphere, and combined with three dimensional reconstruction of solar magnetic fields, makes numerical short-term (within hours to days) solar activity forecasting possible. In the current report, we propose the erupting frequency and main attack direction of solar eruptions as new forecasts and present the prospects for numerical short-term solar activity forecasting based on the magnetic topological framework in solar active regions.

Solar Radio Emission as a Prediction Technique for Coronal Mass Ejections’ Detection

2017 ◽  
Vol 13 (S335) ◽  
pp. 321-323
Author(s):  
Vladimir M. Fridman ◽  
Olga A. Sheiner
Keyword(s):  
Statistical Analysis ◽  
Radio Emission ◽  
Coronal Mass Ejections ◽  
Solar Radio ◽  
Solar Radio Emission ◽  
Short Term ◽  
Prediction Technique ◽  
Solar Coronal

AbstractIn this report we present a possible scheme of short-term CME detection forecasting developed on the basis of statistical analysis of solar radio emission regularities prior to “isolated” solar Coronal Mass Ejections registered in 1998, 2003, 2009-2013.

scholarly journals Solar activity and solar oscillations

1997 ◽  
Vol 181 ◽  
pp. 277-285
Author(s):  
Y. Elsworth
Keyword(s):  
Magnetic Field ◽  
Solar Activity ◽  
Radio Emission ◽  
Surface Temperature ◽  
The Sun ◽  
Solar Oscillations ◽  
Thermal Component ◽  
X Ray ◽  
Convective Flows ◽  
Wide Range

Helioseismology provides us with the tools to probe solar activity. So that we can consider how the solar oscillations are influenced by that activity, we first consider the phenomena that we associate with the active Sun. The surface of the Sun is not quiet but shows evidence of convection on a wide range of scales from a few hundred kilometres through to several tens-of-thousands of kilometres. The surface temperature shows signs of the convection structures with the temperature in the bright granules being some 100 K to 200 K hotter than the surrounding dark lanes. Sunspots, which are regions of high magnetic field that suppress convective flows, are clearly visible to even quite crude observations. They are several tens-of-thousands of kilometres in diameter and about 2000 K cooler than their surroundings. Ultraviolet and X-ray pictures from satellites show that the higher layers of the solar atmosphere are very non-uniform with bright regions of high activity. Contemporaneous magnetograms show that these regions are associated with sunspots. Flares - regions of magnetic reconnections - are seen at all wavelengths from X-ray through the visible to radio. They are the non-thermal component of the radio emission of the Sun. There are many other indicators of activity on the Sun.

scholarly journals Some patterns in the development of centers of solar activity, 1962–66

1968 ◽  
Vol 35 ◽  
pp. 56-63 ◽  
Author(s):  
Helen W. Dodson ◽  
E. Ruth Hedeman
Keyword(s):  
Solar Activity ◽  
Radio Emission ◽  
Differential Rotation ◽  
Graphical Representation ◽  
Past History ◽  
The Sun ◽  
Active Centers ◽  
Opposite Hemisphere ◽  
The Past ◽  
History Of

A graphical representation of the 66 solar rotations (Carrington) between January 1, 1962 and December 31, 1966 has been prepared. It includes all centers of activity for which the calcium plage attained an area of at least 1000 millionths of the solar hemisphere and/or intensity 3 (McMath scale). In this study the antecedents, descendents, and neighbors of each region can easily be discerned. The work shows clearly that zones of activity, apparently closely related and much larger than single plages existed for long intervals of time. For example, the significant increases in solar activity in February, May, and October of 1965 occurred in a ‘family’ of calcium plages apparently related through similarities of position and strong radio emission.The members of ‘families’ of centers of activity are found at systematically changing longitudes. For some ‘families’ the change of longitude appears to be primarily a consequence of differential rotation; for others, the pattern of formation of active centers dominates.According to the data for 1962–66 a meaningful study of the development of a center of activity may require consideration not only of the past history of the zone of the Sun in which it occurs but also of the zone approximately 180° away on the opposite hemisphere.

Influence of short-term changes in solar activity on baric field perturbations in the stratosphere

1997 ◽  
Vol 59 (11) ◽  
pp. 1233-1244 ◽  
Author(s):  
A.S. Besprozvannaya ◽  
G.I. Ohl ◽  
B.I. Sazonov ◽  
I.A. Scherba ◽  
T.I. Schuka ◽  
...  
Keyword(s):  
Solar Activity ◽  
Short Term
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