Sun 140529, radiation of types I II III IV V

Many thanks to the Taxpayers of France, the Nancay Decametric Array Team at the Nancay Radio Astronomy Station of Paris Observatory, Trinity College Dublin Ireland Astrophysics Group, NOAA SWPC, and NASA SDO HMI Magnetograph Team.

The vertical scale is hours and minutes of Universal Time
The horizontal scale is MHz
The dynamic range from black to white is 30 dB

Sun 140527, selected spectra of types I II III radiation

Many thanks to the Taxpayers of France, the Nancay Decametric Array Team at the Nancay Radio Astronomy Station of Paris Observatory, Trinity College Dublin Ireland Astrophysics Group, NOAA SWPC, and NASA SDO HMI Magnetograph Team.

The vertical scale is hours and minutes of Universal Time
The horizontal scale is MHz
The dynamic range from black to white is 20 dB

Konovalenko and 14 collaborators - Solar simultaneous observations with STEREO WAVES and UTR-2

I take note of Konovalenko, A. A.; Stanislavsky, A. A.; Rucker, H. O.; Lecacheux, A.; Mann, G.; Bougeret, J.-L.; Kaiser, M. L.; Briand, C.; Zarka, P.; Abranin, E. P.; Dorovsky, V. V.; Koval, A. A.; Mel'nik, V. N.; Mukha, D. V.; Panchenko, M., 2013: "Synchronized observations by using the STEREO and the largest ground-based decametre radio telescope"

http://adsabs.harvard.edu/abs/2013ExA....36..137K

Abstract: "We consider the approach to simultaneous (synchronous) solar observations of radio emission by using the STEREO-WAVES instruments (frequency range 0.125-16 MHz) and the largest ground-based low-frequency radio telescope. We illustrate it by the UTR-2 radio telescope implementation (10-30 MHz). The antenna system of the radio telescope is a T-shape-like array of broadband dipoles and is located near the village Grakovo in the Kharkiv region (Ukraine). The third observation point on the ground in addition to two space-based ones improves the space-mission performance capabilities for the determination of radio-emission source directivity. The observational results from the high sensitivity antenna UTR-2 are particularly useful for analysis of STEREO data in the condition of weak event appearances during solar activity minima. In order to improve the accuracy of flux density measurements, we also provide simultaneous observations with a large part of the UTR-2 radio telescope array and its single dipole close to the STEREO-WAVES antennas in sensitivity. This concept has been studied by comparing the STEREO data with ground-based records from 2007-2011 and shown to be effective. The capabilities will be useful in the implementation of new instruments (LOFAR, LWA, MWA, etc.) and during the future Solar Orbiter mission."

Source of UTR-2 images below: Google Maps and Images

Solar and Jovian radiation 140430 and 140510 at STEREO WAVES

Many thanks to the STEREO WAVES Team

Reid Vilmer Kontar 2014 - Type III starting frequencies and hard X-rays

I take note of Reid, Hamish A. S.; Vilmer, Nicole; Kontar, Eduard P., 2014
   
"The Low-High-Low Trend of Type III Radio Burst Starting Frequencies and Solar Flare Hard X-rays"

http://adsabs.harvard.edu/cgi-bin/bib_query?arXiv:1403.1839

Abstract: "Using simultaneous X-ray and radio observations from solar flares, we investigate the link between the type III radio burst starting frequency and hard X-ray spectral index. For a proportion of events the relation derived between the starting height (frequency) of type III radio bursts and the electron beam velocity spectral index (deduced from X-rays) is used to infer the spatial properties (height and size) of the electron beam acceleration region. Both quantities can be related to the distance travelled before an electron beam becomes unstable to Langmuir waves. To obtain a list of suitable events we considered the RHESSI catalogue of X-ray flares and the Phoenix 2 catalogue of type III radio bursts. From the 200 events that showed both type III and X-ray signatures, we selected 30 events which had simultaneous emission in both wavelengths, good signal to noise in the X-ray domain and > 20 seconds duration. We find that > 50 % of the selected events show a good correlation between the starting frequencies of the groups of type III bursts and the hard X-ray spectral indices. A low-high-low trend for the starting frequency of type III bursts is frequently observed. Assuming a background electron density model and the thick target approximation for X-ray observations, this leads to a correlation between starting heights of the type III emission and the beam electron spectral index. Using this correlation we infer the altitude and vertical extents of the flare acceleration regions. We find heights from 183 Mm down to 25 Mm while the sizes range from 13 Mm to 2 Mm. These values agree with previous work that places an extended flare acceleration region high in the corona. We analyse the assumptions required and explore possible extensions to our assumed model. We discuss these results with respect to the acceleration heights and sizes derived from X-ray observations alone."