We examine the energetics of coronal mass ejections (CMEs) with data from the large-angle spectrometric coronagraphs (LASCO) on SOHO. The LASCO observations provide fairly direct measurements of the mass, velocity, and dimensions of CMEs. Using these basic measurements, we determine the potential and kinetic energies and their evolution for several CMEs that exhibit Ñux-rope morphologies. Assuming Ñux conservation, we use observations of the magnetic Ñux in a variety of magnetic clouds near the Earth to determine the magnetic Ñux and magnetic energy in CMEs near the Sun. We Ðnd that the potential and kinetic energies increase at the expense of the magnetic energy as the CME moves out, keeping the total energy roughly constant. This demonstrates that Ñux-rope CMEs are magnetically driven. Furthermore, since their total energy is constant, the Ñux-rope parts of the CMEs can be considered a closed system above D2 R _ .

Solar radio observations provide a unique diagnostic of the outer solar atmosphere. However, the inhomogeneous turbulent corona strongly affects the propagation of the emitted radio waves, so decoupling the intrinsic properties of the emitting source from the effects of radio wave propagation has long been a major challenge in solar physics. Here we report quantitative spatial and frequency characterization of solar radio burst fine structures observed with the Low Frequency Array, an instrument with high-time resolution that also permits imaging at scales much shorter than those corresponding to radio wave propagation in the corona. The observations demonstrate that radio wave propagation effects, and not the properties of the intrinsic emission source, dominate the observed spatial characteristics of radio burst images. These results permit more accurate estimates of source brightness temperatures, and open opportunities for quantitative study of the mechanisms that create the turbulent coronal medium through which the emitted radiation propagates.

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We report the results of our investigation of interplanetary e †ects caused by the large solar Ñare (X5.7/ 3B) that occurred on 2000 July 14. In association with this event a bright, fast, halo coronal mass ejection (CME) was observed. The analysis of multiwavelength, high-cadence images obtained from the Radioheliograph shows the on-disk signatures of the initiation of the CME at low-coronal NancÓ ay heights, ¹2The formation of the CME inferred from the radio data indicates a nearly developed R _ . halo at the low corona. The white-light images and CME follow-up measurements in the interplanetary medium also show, in agreement with the radio data, the propagation of the fully developed halo CME. The inference on the consequences of the CME in the inner heliosphere is from the interplanetary scintillation (IPS) observations obtained with the Ooty Radio Telescope and multiantenna system at the SolarTerrestrial Environment Laboratory. Scintillation measurements at Ooty on a grid of a large number of radio sources provided an opportunity to image the disturbance associated with the CME at di †erent distances from the Sun before its arrival at the near-Earth space. The scintillation data in particular also played a crucial role in understanding the radial evolution of the speed of the CME in the inner heliosphere. The "" speed-distance ÏÏ plot indicates a two-level deceleration : (1) a low decline in speed at distances within or about 100 solar radii and (2) a rapid decrease at larger distances from the Sun. The linear increase in the size of the CME with radial distance is also brieÑy discussed. The expansion of the CME, formation of the halo in the low corona, and its speed history in the interplanetary medium suggest a driving energy, which is likely supplied by the twisted magnetic Ñux rope system associated with the CME.