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

2018-02-20 348 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

2018-02-06 372 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.*

2018-01-23 352 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.*

2018-01-09 618 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 […]

Propagation and Interaction Properties of Successive Coronal Mass Ejections in Relation to a Complex Type II Radio Burst
by Y. D. Liu et al.*

2017-12-19 670 views

Quantifying how coronal mass ejections (CMEs), particularly fast ones, propagate from the Sun to the Earth is an overarching issue in CME research and space weather forecasting. A typical fast CME would finish its major deceleration well before reaching 1 AU (Liu et al. 2013). The actual situation of CME Sun-to-Earth propagation, however, may involve interactions with the highly structured solar wind including other CMEs. Interactions involving more than two […]

Critical Fluctuations in Beam-Plasma Systems and Solar Type III Radio Bursts
by G. Thejappa and R. J. MacDowall

2017-12-05 524 views

The type III radio bursts are the most intense radio emissions from the sun. In Figure 1, we present a typical type III burst observed by the STEREO spacecraft. Ginzburg and Zheleznyakov (1958) were the first to suggest that Langmuir waves excited by the solar flare accelerated electrons are the source of these bursts. The in situ detection of electron beams and Langmuir waves in association with type III bursts […]

Observations of solar radio burst fine structures with LOFAR
by E. Kontar et al.*

2017-11-28 1,180 views

During solar flares, electrons are accelerated up to relativistic speeds. As they propagate upwards through the solar corona, they produce so-called type III radio bursts. These type III bursts often demonstrate fine structure, with their spectra consisting of multiple narrowband “striae”; most likely, these structures are caused by small-scale density inhomogeneities of the coronal plasma so that the subsequent fundamental plasma processes that produce the radio bursts is produced in […]

VLA Measurements of Faraday Rotation through Coronal Mass Ejections
by Jason E. Kooi et al*

2017-11-21 402 views

Coronal mass ejections (CMEs) are large-scale eruptions of ionized gas (or plasma) from the Sun. The ejected material of a CME is associated with strong magnetic fields, which can cause substantial geomagnetic storms at Earth that enhance the radiation space environment and affect global communications and geolocation. Remote-sensing techniques such as Faraday rotation (FR), the rotation of the plane of polarization of linearly polarized radiation as it propagates through a […]

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