Solar Type-IIIb Radio Bursts as Tracers for Electron Density Fluctuations in the Corona
by V. Mugundhan et al.*

2018-04-17 138 views

Type III bursts are generated when an electron accelerated close to speed of light excite the layers of coronal plasma they encounter when travelling away from the sun. These bursts are seen in a time-frequency-intensity image (called dynamic spectrum, as the time variation of the spectrum is visualized by it) as a bright patch, drifting from high to low frequencies on short time-scales ($\approx$ few-seconds). At times, along the path […]

New evidence for a coronal mass ejection driven fast drifting type II radio burst
by K. Anshu et al.

2018-04-03 524 views

Type II solar radio bursts are considered to originate from plasma waves excited by magnetohydrodynamic (MHD) shocks and converted into radio waves at the local plasma frequency and its harmonics. Type II radio bursts are mostly associated with coronal mass ejections (CMEs) and flares Nindos et al. (2008). We studied a seldom occurring high frequency type II burst on 4th Novemeber 2015, which had both fundamental and harmonic components. The […]

Association of radio polar cap brightening with bright patches and coronal holes
by C. L. Selhorst et al.*

2018-03-20 284 views

The purpose of this work is to model the emission of 17 GHz polar bright patches, which are frequently observed by the Nobeyama Radioheliograph (NoRH) in association with coronal holes. Although these bright regions have been observed for a few decades, their nature remains unclear. Our simulations were based on the temperature and density profiles from the SSC atmospheric model (Selhorst et al., 2005), with modifications to include a coronal […]

Dressing the Coronal Magnetic Extrapolations of Active Regions with a Parameterized Thermal Structure
by Gelu M. Nita et al.

2018-03-06 355 views

The study of time-dependent solar active region morphology and its relation to eruptive events requires analysis of imaging data obtained in multiple wavelength domains with differing spatial and time resolutions, ideally in combination with 3D physical models. To facilitate this goal, we have undertaken a major enhancement of our IDL-based simulation tool, GX Simulator, originally developed for modeling microwave and X-ray emission from flaring loops (Nita et al. 2015), to […]

Solar ALMA observations: constraining the chromosphere above sunspots
by M. Loukitcheva et al.*

2018-02-20 552 views

Our understanding of sunspots is far from complete despite intensive research over hundreds of years. Radiation at submillimeter and millimeter wavelengths is formed in local thermodynamic equilibrium (LTE) in the low to mid chromosphere, and its intensity depends linearly on the ambient temperature of the medium. Observations at these wavelengths thus provide important diagnostics of sunspot chromospheres (Loukitcheva et al. 2014). The largest radio telescope in the world, the Atacama […]

Synergy of stochastic and systematic energization of plasmas during turbulent reconnection
by Th. Pisokas, L. Vlahos and H. Isliker

2018-02-06 438 views

In the current literature the acceleration of particles during solar flares is attributed to either weak turbulence or to large scale Unstable Current Sheet (UCS). The way UCS drive weak turbulence in a separated volume on the loop top or inside the loops below the UCS was never been presented in detail. During the last thirty years the plasma physics community developed the concept of turbulent reconnection. This concept went unnoticed […]

The statistical relationship between global EUV waves and other solar phenomena
by D. Long et al.*

2018-01-23 374 views

Solar eruptions are associated with a variety of different phenomena, including solar flares, coronal mass ejections, Type II radio bursts, solar energetic particles and global coronal EUV waves (commonly known as “EIT waves”, e.g., Warmuth, 2015). However, the relationship between global waves and these other phenomena is not well defined. Although global waves have traditionally been studied using single event case studies, several statistical studies have been performed, with Thompson […]

Estimation of a CME magnetic field strength using observations of gyrosynchrotron radiation
by E. P. Carley et al.*

2018-01-09 668 views

Despite many years of study, the dominant driver and energy source of coronal mass ejections (CMEs) is still under investigation. Observational studies have indicated that magnetic energy represents the largest part of the total energy budget of the eruption (Emslie et al., 2012, Carley et al., 2012). However, despite having such a dominant influence on CME dynamics, little is known about CME magnetic field. This is due to the scarcity […]

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