The Nobeyama radioheliograph

Nakajima, Hiroshi; Nishio, Makoto; Énomé, Shinzo; Shibasaki, Κ.; Takano, Toshiaki; Hanaoka, Yoichiro; Torii, Chikayoshi; Sekiguchi, H.; Bushimata, Takeshi; Kawashima, Susumu; Shinohara, N.; Irimajiri, Yoshihisa; Koshiishi, H.; Kosugi, T.; Shiomi, Y.; Sawa, M.; Kai, K.

doi:10.1109/5.284737

Cited by 438 publications

(235 citation statements)

References 4 publications

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“…In the White event, the immeasurably low heating may perhaps not be unexpected due to the weakness of the nonthermal emission, whose radio flux did not exceed a couple of sfu even at the flare peak time. However, a comparably cold, dense flare with a radio flux more than two orders of magnitude larger has been reported by Bastian et al (2007) based on the combination of the microwave data jointly obtained with the Owens Valley Solar Array (OVSA, Hurford et al 1984;Gary & Hurford 1994), Nobeyama Radio Polarimeters (Torii et al 1979), and the Nobeyama RadioHeliograph (Nakajima et al 1994). From the detailed analysis of the radio spectral evolution and timing in the event, along with quantitative estimates of the fast electron acceleration efficiency, loss, and energy partitions, Bastian et al (2007) concluded in favor of the stochastic acceleration of electrons in this flare, waveturbulence-mediated transport of the electrons, and acceleratedelectron-driven moderate heating of the originally cold, dense plasma of the flaring loop, which was identified as the very site where the energy release and electron acceleration happened.…”

Section: Introductionmentioning

confidence: 99%

Validation of the Coronal Thick Target Source Model

Fleishman

Nita

et al. 2016

ApJ

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We present detailed 3D modeling of a dense, coronal thick-target X-ray flare using the GX Simulator tool, photospheric magnetic measurements, and microwave imaging and spectroscopy data. The developed model offers a remarkable agreement between the synthesized and observed spectra and images in both X-ray and microwave domains, which validates the entire model. The flaring loop parameters are chosen to reproduce the emission measure, temperature, and the nonthermal electron distribution at low energies derived from the X-ray spectral fit, while the remaining parameters, unconstrained by the X-ray data, are selected such as to match the microwave images and total power spectra. The modeling suggests that the accelerated electrons are trapped in the coronal part of the flaring loop, but away from where the magnetic field is minimal, and, thus, demonstrates that the data are clearly inconsistent with electron magnetic trapping in the weak diffusion regime mediated by the Coulomb collisions. Thus, the modeling supports the interpretation of the coronal thick-target sources as sites of electron acceleration in flares and supplies us with a realistic 3D model with physical parameters of the acceleration region and flaring loop.

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Section: Introductionmentioning

confidence: 99%

Validation of the Coronal Thick Target Source Model

Fleishman

Nita

et al. 2016

ApJ

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“…In order to analyse the effect of the array configuration in imaging quality, we considered three different shape arrays (T-array, Y-array, and the spiral array), each array consist of 40 antennas together with the same maximum and minimum baseline. The maximum baseline is 3 km, and the minimum baseline is 8 m. The antenna position of T-array follows the NORH (Nakajima et al 1994), the array configuration is a multiply-equally-spaced T-array. The configuration of Y-array is designed to be another multiply-equally-spaced array, and make each arm differ by 120 • like VLA (Thompson et al 1980).…”

Section: The Array Configurationmentioning

confidence: 99%

“…CASA also takes advantage of the speed, large internal memory, and graphics capabilities to provide a fast and flexible data reduction environment for the astronomer, so here we use CASA to image the sun at radio wavelengths and present some simulations using models based on NORH and SDO/AIA data (Nakajima et al 1994;Lemen et al 2012). In these simulations, the radio image from the NORH and EUV image from the SDO/AIA are used as the simulation models, processing them through MUSER-I and comparing with the actual images (Lüdke, et al 2000;White et al 2003).…”

Section: Image Simulation Using Casamentioning

confidence: 99%

“…However, the available radio imaging observations are presently only at a few discrete frequencies in the range 150-450 MHz from Nancay Radioheliograph (Kerdraon et al 1997), at 5.7 GHz from Siberian Solar Radio Telescope (Grechnev et al 2003), and at 17 and 34 GHz from Nobeyama Radioheliograph (NORH) (Nakajima, Nishio, & Enome 1994). Therefore, a new instrument which is capable of true imaging spectroscopy, with high temporal, spatial, and spectral resolutions is needed (Gary et al 2004).…”

Section: Introductionmentioning

confidence: 99%

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Image Simulation for Mingantu Ultrawide Spectral Radioheliograph in the Decimetre Wave Range

Yan

Wang

et al. 2015

Publ. Astron. Soc. Aust.

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The MUSER is a solar-dedicated radio interferometric array, which will observe the Sun over a wide range of radio frequencies (0.4-15 GHz), and make high time, space and frequency resolution images of the Sun simultaneously. MUSER is located in Mingantu Station in Inner Mongolia of China, which is about 400 kilometres away from Beijing. MUSER consists of two arrays: MUSER-I and MUSER-II. MUSER-I contains 40 antennas with 4.5-m aperture operating at 400 MHz to 2 GHz. MUSER-II contains 60 antennas with 2-m aperture operating at 2 to 15 GHz. Currently, MUSER has already been established and entered into the stage of test observation. This work is focus on the imaging performance of MUSER-I. This paper introduces MUSER-I briefly, presents the analysis of the array configurations, and evaluates the image quality mainly using the dynamic range, fidelity index, and the peak signal-to-noise ratio, also make some actual solar model simulations with CASA, the results will be shown below.

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“…Imaging spectroscopy over centimeter and decimetric wavelengths is important for addressing the problems of primary energy release, particle acceleration, and transportation processes (Bastian, et al 1998, Gary & Keller 2004, Aschwanden 2004, Pick & Vilmer 2008 From statistical study of radio dynamic spectral observations it was inferred that the acceleration site is located in a low-density region with a density of n acc e ∼ 3 × 10 9 cm 3 , corresponding to a plasma frequency of ν p ∼ 500MHz, from where electron beams are accelerated in upward (type III) and downward (RS bursts) directions (Aschwanden & Benz 1997). However, the available radio imaging observations are presently only at a few discrete frequencies in the range 40 -150 MHz from Gauribidanur Radioheliograph (Ramesh et al 1998), in the range 150 -450 MHz from Nancay Radioheliograph (Radioheliograph Group, 1989), at 5.7 GHz from Siberian Solar Radio Telescope (Grechnev et al 2004), and at 17/34 GHz from Nobeyama Radioheliograph (Nakajima et al 1994).…”

Section: Motivationmentioning

confidence: 99%

Radio imaging-spectroscopy observations of the Sun in decimetric and centimetric wavelengths

et al. 2012

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Abstract. To address fundamental processes in the solar eruptive phenomena it is important to have imaging-spectroscopy over centimetric-decimetric wave range. The Chinese Spectral Radioheliograph (CSRH) in 0.4-15 GHz range with high time, space and frequency resolutions is being constructed to achieve this goal. The perspectives to open new observational windows on solar flares and CMEs will be achieved by mapping the radio emission from unstable electron populations during the basic processes of energy release. CSRH is located in a radio quiet region in Inner Mongolia of China. The array of CSRH-I in 0.4-2.0 GHz with 40 4.5m antennas has been established and starts test observations. The 60 2m antennas for array of CSRH-II in 2-15 GHz have been mounted and assembled. The progress and current status of CSRH are introduced.

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The Nobeyama radioheliograph

Cited by 438 publications

References 4 publications

Validation of the Coronal Thick Target Source Model

Validation of the Coronal Thick Target Source Model

Image Simulation for Mingantu Ultrawide Spectral Radioheliograph in the Decimetre Wave Range

Radio imaging-spectroscopy observations of the Sun in decimetric and centimetric wavelengths

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