Abstract.We compare the near-Sun and near-Earth mani•hstations of solar eruptions that occurred during November 1994 to June 1998. We compared white-light coronal mass ejections, metric type II radio bursts, and extreme ultraviolet wave transients (near the Sun) with interplanetary (IP) signatures such as decameter-hectometric type II bursts, kilometric type II bursts, IP ejecta, and IP shocks. We did a two-way correlation study to (1) suggesting that the shocks have a much larger extent than the drivers. Shocks originating from both limbs of the Sun arrived at Earth, contradicting earlier claims that shocks from the west limb do not reach Earth. These shocks also had good type II radio burst association. We provide an explanation •br the observed relation between metric, decameter-hectometric, and kilometric type II bursts based on the fast mode magnetosonic speed profile in the solar atmosphere.

We report on the properties of radio-quiet ( RQ) and radio-loud (RL) coronal mass ejections (CMEs) that are fast and wide (FW ). RQ CMEs lack type II radio bursts in the metric and decameter-hectometric ( DH ) wavelengths. RL CMEs are associated with metric or DH type II bursts. We found that $40% of the FW CMEs from 1996 to 2005 were RQ. The RQ CMEs had an average speed of 1117 km s À1 compared to 1438 km s À1 for the RL, bracketing the average speed of all FW CMEs (1303 km s À1 ). The fraction of full halo CMEs (apparent width ¼ 360 ) was the largest for the RL CMEs (60%), smallest for the RQ CMEs (16%), and intermediate for all FW CMEs (42%). The median soft X-ray flare size for the RQ CMEs (C6.9) was also smaller than that for the RL CMEs (M3.9). About 55% of RQ CMEs were back sided, while the front-sided ones originated close to the limb. The RL CMEs originated generally on the disk with only $25% being back sided. The RQ FW CMEs suggest that the Alfvén speed in the low-latitude outer corona can often exceed 1000 km s À1 and can vary over a factor of !3. None of the RQ CMEs was associated with large solar energetic particle events, which is useful information for space weather applications.

[1] We report on the detection of a new class of nonthermal radio emission due to the interaction between two coronal mass ejections (CMEs). The radio emission was detected by the Radio and Plasma Wave Experiment (WAVES) on board the Wind satellite, while the CMEs were observed by the white-light coronagraphs of the Solar and Heliospheric Observatory (SOHO) mission. There was no type II radio burst (metric or interplanetary) preceding the nonthermal emission. The radio emission occurred at a distance beyond 10 R s from the Sun, where the two CMEs came in contact. Using H-alpha and EUV images, we found that the two CMEs were ejected roughly along the same path. We argue that the nonthermal electrons responsible for the new type of radio emission were accelerated due to reconnection between the two CMEs and/or due to the formation of a new shock at the time of the collision between the two CMEs.

Abstract. During a 16-day period from February 5 to 20, 2000, a series of decametric-tokilometric wavelength type II and type III radio events was observed by the WAVES radio experiment on board the Wind spacecraft. These radio events were related to observed coronal mass ejections (CMEs) and their associated flares. Each of the solar eruptive events was initiated by an intense, complex type III radio burst, which occurred within minutes of the liftoff on the CME. Some of the CMEs produced decametric-hectometric (D-H) type II radio emissions, which, when their frequency drift rates were sufficiently well defined, were used to provide a speed estimate. The complex type III and D-H type II radio emissions gave an indication of the presence of a CME well before the CME was first observed in the coronagraph images. This series of CMEs also generated interplanetary (kilometric) type II radio emissions that tracked the CMEassociated shock through the interplanetary medium and established the terrestrial connection. Thus the various radio emissions associated with these solar eruptive events provided a global view of each entire Sun-Earth connection event, from the initiation and liftoff of the CME at the Sun, to the propagation of the CME-associated shock through the solar corona and interplanetary medium, to its arrival at 1 AU. Finally, we show that simultaneous Wind/Ulysses observations of the interplanetary type II radio emissions on February 9 -10 provide important information on the nature of the type II emission, on the type II source locations, and on the radiation characteristics of the type II emissions. For example, these simultaneous observations clearly indicate that the sporadic nature of the type II radiation was intrinsic to the radio source region.

Abstract. We present an analysis of radio emissions associated with the April 7, 1997 solar eruptive event. The event consisted of a filament disappearance, a complex twophase coronal mass ejection (CME), and a C6.9, 2N flare. At the same time, intermittent type II radio emissions in the frequency range 1-10 MHz, corresponding to an altitude range of 2-15 Ro, were observed by the Wind/WAVES radio receiver. Using the onset times and inferred heights and speeds of the radio bursts, we considered both a CME-driven shock and a flare-associated blast wave shock as possible causes of the type I! radio emissions. We conclude that some of the radio emissions in the WAVES data are associated with each shock. The type II radio emissions associated with the blast wave shock were farther from the sun than any emission of this type that has been reported previously.