Community of European Solar Radio Astronomers – Page 26

Particle Acceleration and heating by turbulent reconnection
by L. Vlahos, T. Pisokas, H. Isliker, V. Tsiolis and A. Anastasiadis

2016-08-09

Fermi (1949) introduced a fundamental stochastic process to solve the problem of particle energization (heating and/or acceleration) in space and astrophysical plasmas. The initial idea of Fermi with randomly moving scatterers (magnetic clouds), was soon replaced with a spectrum of low amplitude (δΒ/Β<<1) waves and termed particle acceleration by MHD (weak) turbulence. In the other extreme, isolated turbulent shock waves or isolated unstable current sheets (UCS) were studied. The regime […]

Observation of a Quasi-periodic Pulsation in Hard X-Ray, Radio, and Extreme-ultraviolet Wavelengths
by Pankaj Kumar, Valery M. Nakariakov and Kyung-Suk Cho

2016-08-02

Quasi-periodic pulsations (QPPs) with periods from a few seconds to several minutes are often observed during solar/stellar flares in X-ray, radio, and optical wavelength bands. The study of QPPs is useful to understand the physical mechanism for the energy release, plasma heating, and particle acceleration during solar flares…

Radio emission and relativistic proton acceleration in the large solar particle event of 20 Jan 2005
by Karl-Ludwig Klein and Sophie Masson

2015-01-16

Energetic particle acceleration Enhanced fluxes of solar energetic particles (SEP) – so-called SEP events – result from processes of explosive energy conversion in the corona, notably flares and coronal mass ejections. The highest energies of solar energetic nucleons detected in space or through gamma-ray emission in the solar atmosphere are in the GeV range. Where and how the particles are accelerated is still controversial. The most debated candidate processes are […]

Signatures of Magnetoacoustic Wave Trains in Solar Decimetric Radio Type IV Bursts
by Hana Mészárosová, Marian Karlický, Ján Rybák, and Karel Jiricka

2009-11-09

It has been theoretically predicted (Roberts et al. 1983, 1984) that the periodicity of magnetoacoustic modes can be modified by the time evolution of an impulsively generated signal. One of the obvious sources of such a disturbance is the impulsive flare process. These magnetoacoustic waves are trapped in regions with higher density (e.g., in coronal loops) acting as waveguides. The impulsively generated wave in such a coronal waveguide exhibits three […]

Sixty-five years of solar radioastronomy – review paper published
by Monique Pick and Nicole Vilmer

2009-03-18

A review paper presenting the input of 65 years of radio observations has been published in the journal Astronomy and Astrophysics Review, October 2008 issue. The authors, Monique Pick and Nicole Vilmer, present first the historical context starting from the early 1940s and then proceed to show how radio astronomy has contributed to our knowledge in solar and solar-terrestrial physics. The review is focused on radio emission from flares and […]

Topical issue on solar radio physics published
by Ludwig Klein, Silja Pohjolainen and Lidia van Driel Gesztelyi

2008-11-25

Topical issue on solar radio physics published CESRA 2007 Workshop The CESRA workshop in 2007, titled Solar Radio Physics and the Flare-CME Relationship, was held at the University of Ioannina in Greece. Some 70+ participants attended the meeting, which consisted of invited and contributed talks in the mornings and working group discussions and presentations in the afternoons. The topics for the four working groups were 1) pre-flare and pre-CME phase, […]

Fragmented radio emission reveals a shock passing through solar active region loops
by Silja Pohjolainen, Jens Pomoell and Rami Vainio

2008-09-02

Shocks and type II bursts Radio type II bursts are observed in association with flares and coronal mass ejections (CMEs). Metric type II bursts can be observed in dynamic radio spectra as slowly drifting emission lanes, with drift rates approximately 0.1 — 1.0 MHz/s. The start frequency of metric type II bursts is usually at about 100 — 200 MHz. The mechanism behind the bursts is generally assumed to be […]

Type III bursts, magnetic field extrapolations, and the propagation of solar energetic particles
by Karl-Ludwig Klein

2008-08-21

Energetic particle propagation from the Sun to Earth Enhanced fluxes of solar energetic particles (SEP) — so-called SEP events — result from processes of explosive energy conversion in the corona, notably flares and coronal mass ejections. From Parker’s model of the interplanetary magnetic field, it is expected that particles accelerated in the corona reach the Earth, provided they are injected into interplanetary magnetic flux tubes near 50°—60° western longitude. Statistically […]

« 1 … 24 25 26 27 28 »