Nobeyama Radioheliograph (NoRH)

Solar Microwave Polarization Observed by the Newest and Oldest Solar Radio Telescopes by Masumi Shimojo

2024-05-01

Polarization, regardless of wavelength, is one of the key observables for understanding the solar atmosphere because it provides information about magnetic fields, and microwave polarization is also one of them. It can reveal magnetism in the chromosphere, transition region, and corona from the microwave polarization dependencies of opacity and emissivity related to magnetic fields. Although observing solar polarization in the microwave range is not easy, it has a long history […]

Localized Microwave and EUV Bright Structures in an Eruptive Prominence
by J. Huang et al.*

2019-07-30

We study a solar eruptive prominence with flare/coronal mass ejection (CME) event by microwave and extreme ultraviolet (EUV) observations. Its evolution can be divided into three phases: slow rise, fast expansion, and ejection. In the slow-rise phase, the prominence continuously twists for more than one hour with a patch of bright emission appearing around the top. When the north leg interacts with the local small-size loops, the fast expansion is […]

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

2018-03-20

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

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 […]

Observations of a radio-quiet solar preflare
by A. Benz et al.*

2017-10-17

A substantial fraction of the flare energy (as observed e.g. in bolometric luminosity) first appears in non-thermal electrons and ions (Emslie et al. 2012). It implies that the particles are efficiently accelerated to a non-Maxwellian velocity distribution. Most of the non-thermal electrons have energies in the 10 – 30 keV range, but some are accelerated beyond 100 keV and radiate gyro-synchrotron radio emission. Nearly all of the flare energy is […]

Particle acceleration and turbulence during a solar flare
by E.P. Kontar et al.*

2017-06-13

Particle acceleration during solar flares is a highly efficient process, in terms of both the energy (tens of percent of the released magnetic energy can be transferred to the energetic particles) and the particle number (nearly all electrons in the flaring region are accelerated). So-called stochastic acceleration (e.g., Petrosian 2012 for a review) is one of the most popular mechanisms capable of providing these characteristics. In this scenario, the magnetic […]

Diagnostics of the acceleration modulation process based on quasi-periodic variations of flare emission
by Kupriyanova et al.*

2016-09-27

Quasi-periodic pulsations (QPPs) with the characteristic time scales from a few seconds up to tens of minutes are frequently seen in the time profiles of solar and stellar flare emission (Nakariakov et al., 2016 ). Among all the possibilities of QPPs explanation, two reasons are discussed more actively: magnetohydrodynamic (MHD) oscillations in plasma waveguides and periodic reconnection. A solar flare showing clear quasi-periodic pulsations in X-rays, microwaves and followed by […]

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, […]

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