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Keller (eds.), Solar and Space Weather Radiophysics, 17-45. 2004 Kluwer Academic Publishers. Printed in the Netherlands. of bursts (Figure 2.1). With the progress accomplished in the understanding of the physical processes responsible for radio emission, this classification appears somewhat arbitrary now. Figure 2.1. The Sun seen at 17 GHz by the Nobeyama Radioheliograph (left) and at 195 Aby the Extreme-ultraviolet Imaging Telescope (EIT) on SOHO (right) the dark region is a...

Concluding Remarks and the Future of Radio Physics

In the preceding sections, I have attempted to show how solar radio studies have contributed to transform our knowledge of the physics of the corona and of the interplanetary medium, and have been instrumental in the field of solar-terrestrial research. Major spectacular advances can be expected in the future from multi-wavelength observations covering a large spectral range if, however, some specific extensions in radio instrumentation are achieved. The present situation is, indeed, not fully...

Radio emission mechanisms

Radio emission mechanisms are discussed elsewhere in this volume by Gary & Hurford (Chapter 4) and will therefore be only touched on here. The radio spectrum from centimeter to meter wavelengths is rich in diagnostic possibilities because (1) a variety of coherent and incoherent emission processes occur (2) both the optically thin and optically thick portions of emission spectra are accessible to study. Hence, tremendous observational leverage is available to measure or otherwise constrain...

Linear polarization in the outer corona

It appears that linear polarization can be detected within a narrow bandwidth if the QTR, where circular polarization is transformed to linear, is at a sufficient height that the Faraday rotation does not smear the linear polarization to zero. In 1993 the linear polarization was detected by Alissandrakis and Chiuderi Drago (1994) above the AR 7530 in the course of circular polarization sign inversion due to QT-propagation. The observations were made with a multichannel spectral line receiver at...

What is a fast CME

In the past, only a single characteristic value was used to define fast CMEs > 400 km s1 (Cliver et al. 1999). This number can be traced to Gosling et al. (1976) who arrived at the conclusion that, the characteristic speed with which MHD signals propagate in the lower (1.1 to 3 solar radii) corona, where metric wavelength bursts are generated, is about 400 to 500 km s1. Some metric type II bursts are known to be produced by CMEs moving with a speed of only 250 km s1 (see Fig. 1 of Gopalswamy...

FASR instrumental requirements

The instrumental requirements for FASR are determined by the scientific requirements, which have been addressed by the wider solar physics community in a number of workshops. The most recent of these was an international workshop at the NRAO in Green Bank, WV, in 2002. These requirements will be revisited periodically until construction of the instrument begins. In this section, we summarize current specifications and discuss the rationale for choices made in general terms. Specific choices are...

The Frequency Agile Solar Radiotelescope

National Radio Astronomy Observatory*, Charlottesville, VA 22903, USA tbastian nrao.edu Abstract The Frequency Agile Solar Radiotelescope (FASR) will be a ground based solar-dedicated radio telescope designed and optimized to produce high resolution, high-fidelity, and high-dynamic-range images over a broad range of radio frequencies ( 0.05-24 GHz). That is, FASR will perform broadband imaging spec-troscopy, producing unique data and enabling a wide variety of radio-diagnostic tools to be...

Confined and LDE flares

The Skylab data led to a two-element classification of solar flares into confined and eruptive categories (Pallavicini et al. 1977), and this classification appears to work well enough for the Yohkoh data as well ( 6). The confined flares typically appear as small bright loops with little large-scale motion other than that attributed to evaporation flows along the loops the eruptive flares tend to lead to long-decay events (LDEs MacCombie & Rust 1979) with an arcade of loops, and to be more...

IPS measurements

Scintillation-level measurements are available digitally from 1990 October through 1994 September from nearly 1000 sources observed daily at 80 MHz by the Cambridge array telescope. In recent years radio source scintillation-level observations have been obtained from several tens of sources measured each day by the group at the Solar-Terrestrial Environment Laboratory (STELab), Toyokawa City (Nagoya University), Japan. These observations have been available from the STELab Kiso radio telescope...

References

H. & Stone, R. G., 1969, Solar Phys., 8, 388 Aubier, M. G., Leblanc, Y. & Moller-Pederson, B., 1978, A& Ap, 70, 685 Bale, S. D. and Reiner, M. J. and Bougeret, J.-L. and Kaiser, M. L. and Krucker, S. and Larson, D. E. and Lin, R. P. 1999, GRL, 26, 1573 Boishot, A., de la Noe, J. & B. Moller-Pederson, 1970, A& Ap, 4, 159 Boischot, A., Riddle, A. C., Pearce. J. B., & Warwick, J. W., 1980, Solar Phys., 5, 397 Bougeret, J.-L., Fainberg, J., &...

Coronal Magnetography

Coordinated radio and X-ray or EUV observations have been carried out since the Skylab era in attempts to garner information about coronal magnetic fields (Kundu, Schmahl & Gerassimenko 1980 Kundu, Schmahl & Rao 1981 Pallavicini, Sakurai & Vaiana 1981 Shibasaki et al. 1983 Webb et al. 1983, 1987 Holman 1986 Lang et al. 1987ab Brosius, Holman & Schmelz 1991 Nitta etal. 1991 Brosius et al. 1992 1993 Schmelz et al. 1992 1994). The terms radio and microwave are frequently used...

Disadvantages of current radio observations

Difficulties in combining different spectrometer data due to their varying sensitivity, calibration, frequency coverage, RFI environment, etc. Imaging unavailable in many frequencies. Higher sensitivity is needed for both imaging and spectral observations. Physical interpretation of important radio emissions, such as type IIs, is still incomplete. It reduces the scientific return of these radio observations for modeling purposes, for example .