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Astronomy & Astrophysics
Polarisation and source structure of solar stationary type IV radio bursts2020 •
The reconfiguration of the magnetic field during and after a coronal mass ejection (CME) may be accompanied by radio emission from non-thermal electrons. In particular, stationary type IV bursts (also called storm continua) are emitted by electrons in closed magnetic configurations usually located in the wake of the outward-travelling CME. Although stationary type IV bursts, which stand out by their long duration (up to several hours) and strong circular polarisation, have been known for more than fifty years, there have been no systematic studies since the 1980s. In this work we use the data pool of the Nançay Radioheliograph together with white-light coronagraphy, EUV imaging and magnetography from the SoHO, Proba2, SDO and STEREO spacecraft to revisit the source structure and polarisation of a sample of seven well-defined stationary type IV bursts at decimetre-to-metre wavelengths. The radio sources are most often found in one leg, in one case both legs, of the magnetic flux rope...
The Astrophysical Journal
Fine Structures of Solar Radio Type III Bursts and Their Possible Relationship with Coronal Density Turbulence2018 •
Solar radio type III bursts are believed to be the most sensitive signatures of near-relativistic electron beam propagation in the corona. A solar radio type IIIb-III pair burst with fine frequency structures, observed by the Low Frequency Array (LOFAR) with high temporal (∼10 ms) and spectral (12.5 kHz) resolutions at 30-80 MHz, is presented. The observations show that the type III burst consists of many striae, which have a frequency scale of about 0.1 MHz in both the fundamental (plasma) and the harmonic (double plasma) emission. We investigate the effects of background density fluctuations based on the observation of striae structure to estimate the density perturbation in the solar corona. It is found that the spectral index of the density fluctuation spectrum is about −1.7, and the characteristic spatial scale of the density perturbation is around 700km. This spectral index is very close to a Kolmogorov turbulence spectral index of −5/3, consistent with a turbulent cascade. This fact indicates that the coronal turbulence may play the important role of modulating the time structures of solar radio type III bursts, and the fine structure of radio type III bursts could provide a useful and unique tool to diagnose the turbulence in the solar corona.
2018 •
International Letters of Chemistry, Physics and Astronomy
Detailed Investigation of a Moving Solar Burst Type IV Radio Emission in on Broadband Frequency2014 •
The moving type IV burst component of the solar radio region from 260-380 MHz observed using the CALLISTO spectrometer is discussed in detail. We used the Compound Astronomical Low Cost Low Frequency Spectrometer Transportable Observatory (CALLISTO) system connected to the Log Periodic Dipole Antenna (LPDA) at the National Space Centre, Selangor located (3.0833333°N 101.5333333°E) on 22nd February 2012. It is found that a strong burst that caused by extraordinary solar flares are due to magnetic reconnection effect potentially induced in the near-Earth magneto tail. From our observation the indication of signal potentially drives Coronal Mass Ejections (CMEs). We also compare our results with the Geostationary Operational Environmental Satellites (GOES) data. From our analysis, one possible reason behind the formation of this very complex long duration of this loop is the magnetic reconnection and disruption of the loops which is observed during flare maximum. The Active Region, AR ...
The Astrophysical Journal
The origin of the modulation of the radio emission from the solar corona by a fast magnetoacoustic wave2018 •
Observational detection of quasi-periodic drifting fine structures in a type III radio burst associated with a solar flare SOL2015-04-16T11:22, with Low Frequency Array, is presented. Although similar modulations of the type III emission have been observed before and were associated with the plasma density fluctuations, the origin of those fluctuations was unknown. Analysis of the striae of the intensity variation in the dynamic spectrum allowed us to reveal two quasi-oscillatory components. The shorter component has the apparent wavelength of ∼ 2 Mm, phase speed of ∼ 657 km s −1 , which gives the oscillation period of ∼ 3 s, and the relative amplitude of ∼ 0.35%. The longer component has the wavelength of ∼ 12 Mm, and relative amplitude of ∼ 5.1%. The short frequency range of the detection does not allow us to estimate its phase speed. However, the properties of the shorter oscillatory component allowed us to interpret it as a fast magnetoacoustic wave guided by a plasma non-uniformity along the magnetic field outwards from the Sun. The assumption that the intensity of the radio emission is proportional to the amount of plasma in the emitting volume allowed us to show that the superposition of the plasma density modulation by a fast wave and a longer-wavelength oscillation of an unspecified nature could readily reproduce the fine structure of the observed dynamic spectrum. The observed parameters of the fast wave give the absolute value of the magnetic field in the emitting plasma of ∼ 1.1 G which is consistent with the radial magnetic field model.
Astronomy & Astrophysics
Observation of quasi-periodic solar radio bursts associated with propagating fast-mode waves2016 •
In: Mesterek és Tanítványok 2. Tanulmányok a bölcsészet- és társadalomtudományok területéről. Szerk. Czeferner Dóra, Bőhm Gábor, Fedeles Tamás. Pécs 2018. 81–146.
Az uralkodó, a Szentszék és a magyar főpapok Luxemburgi Zsigmond korában [The Monarch, the Holy See and the Hungarian Prelates in the Era of Sigismund of Luxemburg]International Journal of Design & Nature and Ecodynamics
Investigation of Temperature Distribution in a Slab Using Lattice Boltzmann MethodEnergy Sources, Part A: Recovery, Utilization, and Environmental Effects
Consequence of nanoparticle physiognomies on heat transfer characteristics of heat exchanger2019 •
International Journal of Computer Applications
Performance and Maintainability Evaluation of Anti-Spyware System2016 •
Journal for ImmunoTherapy of Cancer
Tumor-associated macrophages in multiple myeloma: advances in biology and therapy2022 •
Geophysical Research Letters
Chlorophyll Fluorescence Better Captures Seasonal and Interannual Gross Primary Productivity Dynamics Across Dryland Ecosystems of Southwestern North America2018 •
Madera Y Bosques
Tension and bending tests in roots of two tropical species2020 •
Romanian Journal of Pediatrics
Comunicarea Diagnosticului Unui Nou-Născut. Importanța Abordării Părinților Şi Copilului2010 •
II. ULUSLARARASI COĞRAFYA EĞİTİMİ KONGRESİ BİLDİRİLER KİTABI (UCEK-2019)
Coğrafi İşaret Tescilli Manisa Kırkağaç Kavununun Üretim ve Ticaretinin Coğrafi Özellikleri (GEOGRAPHICAL CHARACTERISTICS OF PRODUCTION AND TRADE OF MANISA KIRKAĞAÇ MELON REGISTERED BY GEOGRAPHICAL INDICATIONS)2019 •