On the Structure of Magnetic Field and Radioemission of Sunspot-related Source in Solar Active Region T. I. Kaltman, V. M. Bogod St. Petersburg branch of Special Astrophysical Observatory, Russia A. G. Stupishin, L. V. Yasnov Radio Physics Research Institute, St. Petersburg University, Russia

Goal: To develop methods of physical condition diagnostics in the transition region and the lower corona on the base of reconstructed magnetic field and observations of radio emission on RATAN-600 radiotelescope. RATAN-600 characteristics: frequency range: 0.75 … 18.2 GHz 112 frequencies in R and L polarization max. angular resolution: 2 arcsec brightness temperature limit: 5∙10 -5 K To estimate physical conditions in particular active regions with simple configuration AR 10933, AR

AR RATAN-600 scans MDI Source separation 6 GHz 12 GHz 14 GHz 16 GHz

AR 10933: RATAN scans compare with: UV 195Å (EIT) Photosphere Magnetic Field (MDI) Lines of reconstructed Magnetic Field

Magnetic field reconstruction: 1.Source data of 3D photospheric magnetic field – Hinode/SOT instrument Hinode is a Japanese mission developed and launched by ISAS/JAXA, with NAOJ as domestic partner and NASA and STFC (UK) as international partners. It is operated by these agencies in co-operation with ESA and NSC (Norway) degree ambigity was resolved using minimal temperature method ( Metcalf, T.R.: 1994, Solar Phys. 155, 235 ) with optimization suggested at ( Leka, K.D., Barnes, G., Crouch, A.D., Metcalf, T.R., Gary, G. A., Jing, J., Liu, Y.: 2009, Solar Phys. 260, 83 ) (inhomogeneous initial temperature). 3.Potential magnetic field was reconstructed according ( Nakagawa, Y., Raadu, M.A.: 1972, Solar Phys. 25, 127; Allissandrakis, C.E.: 1981, Astron. Astrophys. 100, 197 ) (concerning B z component is not perpendicular to photosphere). 4.On the base of reconstructed potential field (as initial condition) and full 3D magnetic field on photosphere (as boundary condition) non- linear force-free field (NLFFF) was calculated by Landweber iteration algorithm ( Wiegelmann, T.: 2004, Solar Phys. 219, 87 ).

Gyroresonance levels at 3 cm (10 GHz), 3 rd harmonic: at 1.25 Mm at 1.75 MmReconstructed magnetic field – 3D view 3D view AR 10933

Emission transition equation solution: Optical thickness depends on: emission mode (o-, x-mode), wavelength, angle, magnetic field, electron density, electron temperature.

Calculated maps of brightness temperature Effective heights of optical thickness = 1 Observations vs. model Temperature distribution: Obtain calculated scans by convolution with the telescope beam Modify distribution Model parameters adaptation procedure

Model electron temperature and density AR Left polarization Right polarization Observation Model Spectra: observations vs. model

Observations vs. model: scans AR Left Right Observation Model Difference

Effective heights of the free-free emission Spectrum by RATAN-600, gyroresonance (gr) and free-free (ff) emission mechanisms AR 10935

Conclusions Method of active region physical condition diagnostic, based on –multiwave observation of polarized emission in centimetric waverange on RATAN-600, –Magnetic field extrapolation, –Calculation of radioemission allows –To estimate the electron density distribution at different height in different parts of active region, –To estimate the relative contribution of cyclotron and free-free emission at different wavelengths, –To estimate the contribution of various cyclotron emission harmonics, –To correct active region structural component sizes estimations. Analyses based on AR and shows that reconstructed magnetic field corresponds to observed sizes of radiosources at high frequencies, but at low frequencies observed sizes is smaller that modeled ones. It can be solved by introduction of different density and temperature distribution over and outside the spot. Another possible reason is not full adequacy of magnetic field reconstruction. Reconstructed magnetic field of simple one-spot active region can be used to modeling of active region structure and matches well with microwave observations in general. Comparison of observed and calculated radioemission give us the follow estimation of physical condition in analyzed active regions: –Low corona begins at the heights 2.0 … 2.3 Mm, –Corona temperature is 2.5 MK at low heights and, possibly, rises to 3.0 MK higher, –Electron density in low corona is about 1.5 … 1.8∙10 9 cm -3.