Abstract

Radio observations contribute a unique perspective on the many physical phenomena, which occur on the Sun. From thermal bremsstrahlung emission in the quiet solar atmosphere and filaments, to thermal gyroresonance emission in strongly magnetized solar active regions, to the nonthermal emission from MeV electrons accelerated in flares, observations of radio emission provide a powerful probe of physical conditions on the Sun and provide an additional means of understanding the myriad phenomena which occur there. Moreover, radio observing techniques have led the way in developing and exploiting Fourier synthesis imaging techniques. The Nobeyama Radioheliograph, commissioned in June, 1992, soon after the launch of Yohkoh satellite in August, 1991, is the most powerful, solar-dedicated Fourier synthesis in the world, now capable of imaging the full disk of the Sun simultaneously at frequencies of 17 and 34 GHz, with an angular resolution as much as 10" and 5", respectively, and with a time resolution as fine as 100 msec. Between 27-30 October, 1998, the Nobeyama Radio Observatory and the National Astronomical Observatory of Japan hosted the Nobeyama Symposium on Solar Physics with Radio Observations, an international meeting bringing more than sixty participants together at the Seisenryo Hotel in Kiyosato, for a meeting devoted to reviewing recent progress in outstanding problems in solar physics. Emphasis was placed on radio observations and, in particular, radio observations from the very successful Nobeyama Radioheliograph. These results were compared and contrasted with those that have emerged from the Yohkoh mission. In addition, looking forward to the next solar maximum, new instruments, upgrades, and collaborative efforts were discussed. The result is the more than seventy invited and contributed papers that appear in this volume.