Simultaneous monitoring observations of solar active regions at millimeter wavelengths at radio telescopes RT-7.5 BMSTU (Russia) and RT-14 Metsahovi radio observatory (Finland) V.V. Smirnova 1, V.G. Nagnibeda 1, V.S. Ryzhov 2, A.V.Zhiltsov 2, A. Riehokainen 3, J. Kallunki 3,4 1 Astronomical Institute, Saint-Petersburg State University 2 Bauman Moscow State Technical University 3 University of Turku (Finland) 4 Aalto University, Metsähovi Radio Observatory (Finland)

 Scientific mission of the project  Solar active regions (ARs) at millimeter wavelengths: - quasiperiodic oscillations of ARs; - observational properties of millimeter bursts;  First results

New solar observations at millimeter wavelengths: Simultaneous monitoring observations of solar active regions at 37, 93 and 140 GHz! Goals: 1. The investigation of quasi- periodic oscillations of ARs at millimeter waves; 2. The interpretation of millimeter emission properties in solar flares.  RT-7.5: 93GHz (2'.5) and 140 GHz (1'.5); RT-14: GHz, now: 37GHz (2'.4)

Background The investigation of quasi-periodic oscillations of ARs at millimeter waves Oscillating structures Characterize periods Notes Prominences and filaments minGelfreikh et al., 2006 Plums7-20 minOfman, 2000 Spicules5 minScullion et al., 2009 Coronal loops5 sec; minNakariakov and Stepanov, 2007 Sunspots2 min – 160 min and more Kostik, 2004; Gelfreikh, 2006 Because of instruments limitations and atmospheric fluctuations at mm waves, we decided to pay attention to long-period oscillations (>1 min).. Also, there is no clear interpretation of some long periods like 100 min.

First results Long periods were found at the AR (spots!): 20, 30, 100 minutes. The amplitude was different: at 37 GHz some oscillations had lower amplitude than at 93GHz. We supposed, that 100 min. oscillations could be related to the large-scales motions of material above the spot region, or they could be some modes of more global oscillating processes in the spot. We obtained two series of observations from the end of June to and analyzed one of them with continuous wavelet transform (Morlet).

The interpretation of millimeter emission properties in solar flares We analyzed few flare events by GOES class from M to X at microwave-millimeter wavelengths used NoRP data (1, 2, 3.75, 9.4, 17, 35, 80 GHz) with the mm emission excess and GOES 1-8A (for example , X1.7). Light curves contained impulses and the background. The duration of impulses in the radio-burst light-curve ~ 20 s. In spectra: the maximum was shifted to short wavelengths; the spectral flattening was found – not like in classical gyro-synchrotron spectrum. Because of the good known correlation of HXRs and millimeter light-curves, we supposed that the millimeter emission increasing at spectra is related to the injection of high- energetic electrons in the burst source. The same particles could involved in plasma heating processes and provide the shift of the f max to high frequencies in microwave spectra. δ=2.16 (from the hxr spectrum), Ne ≈ 1.1*10 11 cm -3.

We found that in several events the increasing of the flux density in radio light-curves is coincide well with the GOES 1-8A light- curve, that give us the possibility to interpret the background of radio light-curve as a thermal component of the burst radio- emission. We obtained the spectra of the thermal component and estimated the emission measure and number of thermal electrons. EM=5*10 26; ; Ne=7*10 8. The interpretation of millimeter emission properties in solar flares

Summary: The aim of this work is to provide simultaneous monitoring observations of quite active regions (QPO interpretation) and flares at millimeter waves (to obtain the detailed information about spectral properties). The estimation of the dependence of the flux density and the spectral index of non-thermal electrons for 3.2 and 2.2 mm shows that for existing of short mm gyro-synchrotron emission, the spectral index should be less then 4, so the spectrum should be hard. We supposed that mm burst contains thermal and non-thermal components and it reflects in spectra. But the emission mechanism of bursts at mm waves could be not only gyro- synchrotron but some mechanisms could contribute in complex.