Harmonics of Solar Radio Spikes at Metric Wavelengths

Feng, Shiwei; Chen, Yao; Li, Chuanyang; Wang, Bing; Wu, Zhao; Kong, Xiangliang; Du, Qingfu; Zhang, Junrui; Zhao, Guoqing

doi:10.1007/s11207-018-1263-z

Cited by 19 publications

(13 citation statements)

References 27 publications

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“…The decimetric spike emission in Fig. 31 could also be produced by plasma emission (Zheleznyakov and Zaitsev 1975;Kuijpers et al 1981;Ba ´rta et al 2011a, b;Karlicky ´and Ba ´rta 2011;Feng et al 2018;Karlicky ´et al 2021), the accepted mechanism for solar metric type II and type III bursts as well as for fine structure in Type IV bursts (e.g., Kaneda et al 2017). Marque ´et al (2018) write, ''[The ECM emission] mechanism is usually expected to not operate in the solar corona, because of the high electron plasma frequency.…”

Section: Observations Of Extreme Decimetric Radio Burstsmentioning

confidence: 99%

Extreme solar events

Cliver

Schrijver

Shibata

et al. 2022

Living Rev Sol Phys

100

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We trace the evolution of research on extreme solar and solar-terrestrial events from the 1859 Carrington event to the rapid development of the last twenty years. Our focus is on the largest observed/inferred/theoretical cases of sunspot groups, flares on the Sun and Sun-like stars, coronal mass ejections, solar proton events, and geomagnetic storms. The reviewed studies are based on modern observations, historical or long-term data including the auroral and cosmogenic radionuclide record, and Kepler observations of Sun-like stars. We compile a table of 100- and 1000-year events based on occurrence frequency distributions for the space weather phenomena listed above. Questions considered include the Sun-like nature of superflare stars and the existence of impactful but unpredictable solar "black swans" and extreme "dragon king" solar phenomena that can involve different physics from that operating in events which are merely large.

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Section: Observations Of Extreme Decimetric Radio Burstsmentioning

confidence: 99%

Extreme solar events

Cliver

Schrijver

Shibata

et al. 2022

Living Rev Sol Phys

100

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“…Radio spectral observations of type III bursts, spike structures associated with type IV bursts and zebra patterns could also provide estimates of the magnetic field in the coronal source regions of the radio emission [21][22][23]. In addition, when the emission mechanisms are known, microwave imaging at one or more frequencies could be used to produce maps of the coronal magnetic field strength in limited regions [24][25][26][27][28][29].…”

Section: Introductionmentioning

confidence: 99%

Mapping the magnetic field in the solar corona through magnetoseismology

Yang

Tomczyk

Morton

et al. 2020

Sci. China Technol. Sci.

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of magnetic field diagnostics based on observations of magnetohydrodynamic (MHD) waves, has been widely used to estimate the field strengths of oscillating structures in the solar corona. However, previously magnetoseismology was mostly applied to occasionally occurring oscillation events, providing an estimate of only the average field strength or one-dimensional distribution of field strength along an oscillating structure. This restriction could be eliminated if we apply magnetoseismology to the pervasive propagating transverse MHD waves discovered with the Coronal Multi-channel Polarimeter (CoMP). Using several CoMP observations of the Fe xiii 1074.7 nm and 1079.8 nm spectral lines, we obtained maps of the plasma density and wave phase speed in the corona, which allow us to map both the strength and direction of the coronal magnetic field in the plane of sky. We also examined distributions of the electron density and magnetic field strength, and compared their variations with height in the quiet Sun and active regions. Such measurements could provide critical information to advance our understanding of the Sun's magnetism and the magnetic coupling of the whole solar atmosphere.

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“…To demonstrate the present status of the field using such data, in the following, we just present two examples of studies on the temporal delay of solar spikes. Using the spectral data (with a temporal resolution of 10 ms and a spectral resolution of 100 kHz) from the Chashan Solar Observatory (CSO) operated by Shandong University, Feng et al [5] found that the time delay between harmonics of solar radio spikes could be as small as the temporal resolution of the data (∼10 ms), while in an earlier study, Bouratzis et al (2016) found that the duration of metric radio spikes is ∼60 ms according to an analysis of 12,000 events [6] (see Chernov et al [7] for more studies on radio fine structures using high-resolution spectral data).…”

Section: Introductionmentioning

confidence: 99%

“…Mingantu Spectral Radioheliograph (MUSER) [9] generates nearly 3.5 TB data per day. Chashan Solar Observatory (CSO) [6] operated by Shandong University obtains up to 300 GB of data per day. This results in a rapid increase of data volume waiting to be classified and analyzed.…”

Section: Introductionmentioning

confidence: 99%

Auto Recognition of Solar Radio Bursts Using the C-DCGAN Method

Yan

Han

et al. 2021

Front. Phys.

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Solar radio bursts can be used to study the properties of solar activities and the underlying coronal conditions on the basis of the present understanding of their emission mechanisms. With the construction of observational instruments, around the world, a vast volume of solar radio observational data has been obtained. Manual classifications of these data require significant efforts and human labor in addition to necessary expertise in the field. Misclassifications are unavoidable due to subjective judgments of various types of radio bursts and strong radio interference in some events. It is therefore timely and demanding to develop techniques of auto-classification or recognition of solar radio bursts. The latest advances in deep learning technology provide an opportunity along this line of research. In this study, we develop a deep convolutional generative adversarial network model with conditional information (C-DCGAN) to auto-classify various types of solar radio bursts, using the solar radio spectral data from the Culgoora Observatory (1995, 2015) and the Learmonth Observatory (2001, 2019), in the metric decametric wavelengths. The technique generates pseudo images based on available data inputs, by modifying the layers of the generator and discriminator of the deep convolutional generative adversarial network. It is demonstrated that the C-DCGAN method can reach a high-level accuracy of auto-recognition of various types of solar radio bursts. And the issue caused by inadequate numbers of data samples and the consequent over-fitting issue has been partly resolved.

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Harmonics of Solar Radio Spikes at Metric Wavelengths

Cited by 19 publications

References 27 publications

Extreme solar events

Extreme solar events

Mapping the magnetic field in the solar corona through magnetoseismology

Auto Recognition of Solar Radio Bursts Using the C-DCGAN Method

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