Abstract. A two-component (core-halo) emission model has been applied reconciling hard and soft X-ray burst emissions with the microwave burst radiation. The core region is represented by a nonthermal energy distribution (Maxwellian+power law tail) and assumed to be surrounded by a thermal halo. Parameters characterizing the energy distribution and emission measures have been derived numerically from soft and hard X-ray measurements. Using an artificial magnetic field model the microwave flux spectrum has been calculated on the basis of gyro-synchrotron emission and absorption by solving the equation of radiation transfer along the ray trajectories. Open parameters were used to adapt the spectrum to the radio measurements.Thus probable informations about the most appropriate magnetic field parameters as well as about the time-and frequency-dependent source diameters (yielding growth velocities of the core region during the impulsive phase) are deduced for the burst of 1972 May 18 as an example. A fit of the observed spectrum at the burst maximum is consistent with a magnetic field of 1500 G at the core centre decreasing up to about 40 G at the top of the halo at a height of 50 000 km above the centre, a core density of 1020 cm -3 decreasing to 109 cm -3 at the outer halo boundary, and a core diameter of 15 000 km (-20").Due to the simple geometry and emission process adopted,-the model refers primarily to special impulsive bursts. For the representation of broad band microwave bursts, e.g. type IV/x events, a more complex source geometry and/or other variants of the emission mechanism must be invoked.

Model calculations of the S-component are compared with observations of the RATAN-600 telescope at five discrete microwave frequencies referring to active region McMath No. 15974 on May 1, 1979. The spectral variations of source diameter, flux density, and degree of polarization are used to derive the height scale of the magnetic field in accordance with a magnetic dipole distribution under the assumption of advanced temperature and electron density distributions according to most recent EUV observations.

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The solar eclipsc 1966 May 20 was observed at 3.2, 10, 15, 20, 54, 59 cni, 1.05, 1.34 and 2.7 m wavelength b j the observatories of tlie Heinrich-Hertz-Institut. The meter-wavelength observations were superposed b y a noise stormThe result shows a region of enhanced radiation from the plages near the central meridian at the short wavelengths Consulting additionally the observations made at Kiel, N E K h , and OndYejov in thc rcgion of about 1.2 in wavelengtl i t is possible t o localize the source of the noise storm.The annular eclipse 1966 May 30 was observable by the stations of the Heinrich-Hertz-Institut at Berlin-Adlershof, Neustrelitz, and Potsdarn-Tremsdorf, but only as a partial eclipse. Table I shows the optical data of the eclipse at the three stations. The technical parameters of the instruments used for these observations are given in table 2 . T a b l c I . O p t i c a l d a t a of t h e e c l i p s e Results of the measurementsDuring the eclipse period, the sky was cloudy. A t Adlershof, slight rain fell a t the beginning of the eclipse, a t Neustrelitz it was raining near the end of the eclipse, thus influencing slightly the measurements at 3.2 cm wavelength.In figure Ia-c, the occultation curves recorded at the different wavelengths, are shown. The corresponding geometrical occultation curves are given for the three stations too.At 2.7 m wavelength the record is superposed by a noise storm. Therefore the occultation curve is not reproduced here. At 1.05 m and 1-34 m wavelength, however, the influence of this storm was much weaker, so that the occultation curves could be derived from the lower envelope of the records.The undulation at 19.9 cm wavelength in the first part of the occultation curve is due t o ground interference. This effect could not be eliminated, because the records on the days before and after the eclipse as well as on the corresponding day one year before do not show the same interferences,