scholarly journals Spectral Analysis of Solar Radio Type III Bursts from 20 kHz to 410 MHz

2022 ◽  
Vol 924 (2) ◽  
pp. 58
Author(s):  
K. Sasikumar Raja ◽  
Milan Maksimovic ◽  
Eduard P. Kontar ◽  
Xavier Bonnin ◽  
Philippe Zarka ◽  
...  
Keyword(s):  
Solar Radio ◽  
Spectral Response ◽  
Wind Waves ◽  
Wide Frequency Range ◽  
Radio Flux ◽  
Frequency Range ◽  
Data Set ◽  
Type Iii ◽  
Spectral Profiles ◽  
First Time

Abstract We present the statistical analysis of the spectral response of solar radio type III bursts over the wide frequency range between 20 kHz and 410 MHz. For this purpose, we have used observations that were carried out using both spaced-based (Wind/Waves) and ground-based (Nançay Decameter Array and Nançay Radioheliograph) facilities. In order to compare the flux densities observed by the different instruments, we have carefully calibrated the data and displayed them in solar flux units. The main result of our study is that type III bursts, in the metric to hectometric wavelength range, statistically exhibit a clear maximum of their median radio flux density around 2 MHz. Although this result was already reported by inspecting the spectral profiles of type III bursts in the frequency range 20 kHz–20 MHz, our study extends such analysis for the first time to metric radio frequencies (i.e., from 20 kHz to 410 MHz) and confirms the maximum spectral response around 2 MHz. In addition, using a simple empirical model we show that the median radio flux S of the studied data set obeys the polynomial form Y = 0.04X 3 − 1.63X 2 + 16.30X − 41.24, with X = ln ( F MHz ) and with Y = ln ( S SFU ) . Using the Sittler and Guhathakurtha model for coronal streamers, we have found that the maximum of radio power therefore falls in the range 4 to 10 R ⊙, depending on whether the type III emissions are assumed to be at the fundamental or the harmonic.

scholarly journals Spectral Analysis of Solar Radio Type III Bursts from 10 kHz to 80 MHz

2020 ◽  
Author(s):  
Kantepalli Sasikumar Raja ◽  
Milan Maksimovic ◽  
Xavier Bonnin ◽  
Philippe Zarka ◽  
Laurent Lamy ◽  
...  
Keyword(s):  
Solar Radio ◽  
Interplanetary Medium ◽  
Spectral Response ◽  
Wind Waves ◽  
Theoretical Explanation ◽  
Type Iii ◽  
Spectral Profiles ◽  
Field Lines ◽  
Calibration Techniques ◽  
Open Magnetic Field

<p>Solar radio type III bursts are produced by electron beams that are propagating along the open magnetic field lines in the corona and interplanetary medium (IPM). They are the intense, fast drifting, and frequently observed bursts. Recently, it was reported that observations of type III bursts show a maximum spectral response at around 1 MHz. But this behavior of type III bursts is not sufficiently discussed in the literature. In order to understand this behavior we have revisited this problem and studied 2279 isolated type III bursts that are observed with Wind/Waves instrument (from space during 1995-2009) in the frequency range 10 kHz-14 MHz and found that all of them show a maximum spectral response at around 1 MHz. Since type III bursts are somewhat directive, we have studied separately, another 115 type III bursts that are simultaneously observed (in 2013-2014) using Wind/Waves and ground-based facility Nancay Decameter Array (10-80 MHz) and compared the spectral profiles. In this presentation, we will discuss the observations, applied calibration techniques and the possible theoretical explanation of why type III bursts show such behavior. </p>

scholarly journals Solar noise observations from the Alouette satellite

1965 ◽  
Vol 23 ◽  
pp. 357-362
Author(s):  
T. R. Hartz
Keyword(s):  
Solar Radio ◽  
Radio Noise ◽  
Frequency Range ◽  
Sweep Frequency ◽  
Frequency Limit ◽  
Type Iii ◽  
Plausible Model ◽  
Coronal Electron ◽  
Source Velocity ◽  
Lower Frequency Limit

Solar radio noise in the frequency range 1.5 to 10 MHz appears sporadically in the Alouette sweep-frequency recordings above the galactic noise level. The type III bursts can be readily identified, but other spectral types are much more difficult to identify from only the satellite records. Using a plausible model for the coronal electron densities, the Type III frequency drift curves have been interpreted as corresponding to a source velocity in the range 0.1 to 0.15 times the velocity of light. Preliminary estimates have also been made of the coronal temperatures from some of the burst durations.Other solar noise events of longer duration have not been classified other than as enhanced solar noise at this stage. These enhancements frequently show an intensity structure, extending down to the 1.5 MHz lower frequency limit of the equipment. These events are discussed briefly.

scholarly journals Chronology of Formation of Solar Radio Burst Types III and V Associated with Solar Flare Phenomenon on 19th September 2011

2013 ◽  
Vol 24 ◽  
pp. 32-42
Author(s):  
Zety Sharizat Hamidi ◽  
N.N.M. Shariff
Keyword(s):  
Active Region ◽  
Solar Flare ◽  
Solar Radio ◽  
Active Regions ◽  
Radio Flux ◽  
X Ray ◽  
Type Iii ◽  
Solar Bursts ◽  
Type V

The formation of two different solar bursts, type III and V in one solar flare event is presented. Both bursts are found on 19th September 2011 associated with C-class flares on active region 1295. From the observation, we believed that the mechanism of evolution the bursts play an important role in the event. It is found that type V burst appeared in five minutes after type III. There are a few active regions on the solar disk but most are magnetically simple and have remained rather quiet. An interpretation of this new result depends critically on the number of sunspots and the role of active region 1295. Sunspot number is increased up to 144 with seven sunspots can be observed. During that event, the speed of solar wind exceeds 433.8 km/second with 2.0 g/cm3 density of protons in the solar corona. Currently, radio flux is also high up to 150 SFU. The solar flare type C6 is continuously being observed in the X-ray region for 24 hours since 1541 UT and a maximum C1 is detected on 1847 UT. Although the sources of both bursts are same, the direction and ejection explode differently. It is believed that the ejection of particles in a type III burst is higher than solar burst type V.

On the fine structures in interplanetary radio emissions

2020 ◽  
Author(s):  
Immanuel Christopher Jebaraj ◽  
Jasmina Magdalenic ◽  
Stefaan Poedts
Keyword(s):  
Magnetic Field ◽  
Radio Emission ◽  
Radio Source ◽  
Solar Radio ◽  
Wind Waves ◽  
Solar Radio Emission ◽  
Radio Bursts ◽  
Type Ii ◽  
Type Iii ◽  
Fine Structures

<p>Solar radio emission is studied for many decades and a large number of studies have been dedicated to metric radio emission originating from the low corona. It is generally accepted that solar radio emission  observed at wavelengths below the metric range is produced by the coherent plasma emission mechanism. Fine structures seem to be an intrinsic part of solar radio emission and they are very important for understanding plasma processes in the solar medium. Extensive reporting and number of studies of the metric range fine structures were performed, but studies of fine structures in the interplanetary domain are quite rare. New and advanced ground-based radio imaging spectroscopic techniques (e.g. LOFAR, MWA, etc.,) and space-based observations (Wind/WAVES, STEREO/WAVES A & B, PSP, and SolO in the future) provide a unique opportunity to study radio fine structures observed  all the way from metric to kilometric range.</p><p>Radio signatures of solar eruptive events, such as flares and CMEs, observed in the interplanetary space are mostly confined to type II (radio signatures of magneto-hydrodynamic shock waves), and type III  bursts(electron beams propagating along open and quasi-open magnetic field lines). In this study, we have identified, and analyzed three types of fine structures present within the interplanetary radio bursts. Namely, the striae-like fine structures within type III bursts, continuum-like emission patches, and very slow drifting narrowband structures within type II radio bursts. Since space-based radio observations are limited to dynamic spectra, we use the novel radio triangulation technique employing direction finding measurements from stereoscopic spacecraft (Wind/WAVES, STEREO/WAVES A & B) to obtain the 3D position of the radio emission. The novelty of the technique is that it is not dependent on a density model and in turn can probe the plasma density in the triangulated radio source positions (Magdalenic et al. 2014). Results of the study show that locating the radio source helps not only to understand the generation mechanism of the fine structures but also the ambient plasma conditions such as e.g. electron density. We found that fine structures are associated with complex CME/shock wave structures which interact with the ambient magnetic field structures. We also discuss the possible relationship between the fine structures, the broadband emission they are part of, and the solar eruptive events they are associated with.</p>

Molecular relaxation in Chitosan films in GHz frequency range

2014 ◽  
Vol 1613 ◽  
pp. 83-88
Author(s):  
Siva Kumar-Krishnan ◽  
Evgen Prokhorov ◽  
Gabriel Luna-Barcenas
Keyword(s):  
Activation Energy ◽  
Low Frequency ◽  
Bound Water ◽  
Wide Frequency Range ◽  
Frequency Range ◽  
Temperature Range ◽  
A Value ◽  
Chitosan Films ◽  
First Time

ABSTRACTThe molecular relaxations behavior of chitosan (CS) films in the wide frequency range of 0.1-3x109 Hz (by using three different impedance analyzers) have been investigated in the temperature range of -100C to 120°C using Dielectric Spectroscopy (DS). Additionally to the low frequency molecular relaxations such as α and β relaxations, for the first time, high frequency (1-3 GHz) relaxation process has been observed in the chitosan films. This relaxation exhibits Arrhenius-type dependence in the temperature range of -100 C to 54°C with negative activation energy -2.7 kJ/mol. At temperatures above 54°C, the activation energy changes from -2.7 kJ/mol to +4.4 kJ/mol. Upon cooling, the activation energy becomes negative again with a value of -1.2 kJ/mol. The bound water between chitosan molecules strongly modifies molecular motion and the relaxation spectrum, giving rise to a new relaxation at the frequency at ca. 1 GHz. In situ FTIR analysis has shown that this relaxation related to the changes in vibration of the –OH, NH and –CO functional groups.

scholarly journals Dynamics of Flare Processes and Variety of the Fine Structure of Solar Radio Emission over a Wide Frequency Range of 30 – 7000 MHz

Solar Physics ◽  
2014 ◽  
Vol 290 (1) ◽  
pp. 95-114 ◽  
Author(s):  
Gennady Chernov ◽  
Valery Fomichev ◽  
Baolin Tan ◽  
Yihua Yan ◽  
Chengming Tan ◽  
...  
Keyword(s):  
Fine Structure ◽  
Radio Emission ◽  
Solar Radio ◽  
Wide Frequency Range ◽  
Solar Radio Emission ◽  
Frequency Range

scholarly journals A statistical study of solar radio Type III bursts and space weather implication

2020 ◽  
Author(s):  
Theogene Ndacyayisenga ◽  
Jean Uwamahoro ◽  
K. Sasikumar Raja ◽  
Christian Monstein
Keyword(s):  
Space Weather ◽  
Solar Radio ◽  
Statistical Study ◽  
Type Iii

Intuitionistic fuzzy two-factor variance analysis of movie ticket sales

2021 ◽  
pp. 1-11
Author(s):  
Velichka Traneva ◽  
Stoyan Tranev
Keyword(s):  
Comparative Analysis ◽  
Real Data ◽  
Intuitionistic Fuzzy Sets ◽  
Real Numbers ◽  
Data Set ◽  
Important Method ◽  
Ticket Sales ◽  
Intuitionistic Fuzzy ◽  
The One ◽  
First Time

Analysis of variance (ANOVA) is an important method in data analysis, which was developed by Fisher. There are situations when there is impreciseness in data In order to analyze such data, the aim of this paper is to introduce for the first time an intuitionistic fuzzy two-factor ANOVA (2-D IFANOVA) without replication as an extension of the classical ANOVA and the one-way IFANOVA for a case where the data are intuitionistic fuzzy rather than real numbers. The proposed approach employs the apparatus of intuitionistic fuzzy sets (IFSs) and index matrices (IMs). The paper also analyzes a unique set of data on daily ticket sales for a year in a multiplex of Cinema City Bulgaria, part of Cineworld PLC Group, applying the two-factor ANOVA and the proposed 2-D IFANOVA to study the influence of “ season ” and “ ticket price ” factors. A comparative analysis of the results, obtained after the application of ANOVA and 2-D IFANOVA over the real data set, is also presented.

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