The sporadic solar radio emission of patrol solar radio observations within the periods 1980, 1984–1989 and of observations with high temporal and spectral resolution in 1989 are used to find the manifestation of pre CMEs activity.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

More than 40 gradual SEPs have been observed by GOES and SOHO from 2001 to 2003. During 12 SEPs of all these events, energetic electron flux enhancements with energies from 38 keV to 337 keV were observed by RAPID onboard Cluster spacecraft. During these 12 events the variation of the energetic electron flux measured by RAPID/Cluster was closely associated to the variation of the solar energetic proton flux. The observed energetic electron flux was independent on the location of Cluster in the magnetosphere and the background level of magnetospheric electrons (even when the Cluster spacecraft was crossing the magnetopause, the plasma sheet and the low latitude boundary layer). The similar variation of the enhancement of energetic electron flux has also been observed by POLAR and Geotail in some of these events. In some of these events, the electron measurement of RAPID/Cluster will not be contaminated by the SEP protons.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Observations suggest that solar coronal mass ejections (CMEs) are closely associated with reconnection-favored flux emergence, which was explained as the emerging flux trigger mechanism for CMEs by Chen and Shibata (2000) based on numerical simulations. This paper presents a parametric survey of the CME-triggering environment. Our numerical results show that whether the CMEs can be triggered depends on both the amount and the location of the emerging flux. The results are useful for space weather forecast.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

It is an important subject of space weather to forecast accurate arrival time of interplanetary coronal mass ejections (ICMEs) at the Earth. Determination of initial speeds of CMEs is an important factor for this. Here, we estimated the initial speeds of CMEs using solar wind observations near 1 AU and compared these speeds with CME speeds measured by the SOHO coronagraph.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The time and location of magnetic reconnection are indicated by radio (Nobeyama Radio Heliograph and Polarimeters, Hiraiso and Chinese radio spectrographs) and multi-wavelength (SOHO and TRACE satellites) data in a selected flare-CME event on April 21, 2002. Two hour radio burst started at high frequencies (maximum around 10 GHz). After that, a radio ejection at 17 GHz from one foot point was coincident with the expanded flare and post-flare loops. The reversal of polarization sense at the radio loop-top is associated with the strong coherent emissions around 2 GHz, which should be located above the loop-top at 17/34 GHz. The radio ejection and coherent emissions are also associated with a pair of moving type $I\!V$ bursts at 0.2-2 GHz from high to low frequencies and 2.6-3.8 GHz from low to high frequencies, respectively. High time resolution (8 ms) data show three components of the frequency drifts at 2.6-3.8 GHz: very slow (5 MHz/s) of moving type $I\!V$, slow (50 MHz/s) of zebra strips, and fast (several GHz/s) of type $I\!I\!I$, which may represent respectively the speeds of flare loop or current sheet, outflows, and energetic electrons from the reconnection site.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

I discuss in this contribution the accretion and ejection processes occurring in solar-type young stars. Understanding these two important processes, and their link, is one of the major issues in star formation. The magnetic field is thought to play a central role in both extracting the angular momentum from the disk and directing the accretion flow onto the star. I will focus on the well studied T Tauri stars, optically-revealed pre-main sequence stars with ages 1-10 Myrs and mass $\simeq$ 0.5 M$_{\odot}$. In the first part of this contribution, I present the current paradigm for magnetically channeled accretion, where the stellar magnetic field truncates the disk and directs the accretion flow and discuss recent observations, which indicate that this process is non-axisymmetric and time-dependent. I then turn to the study of the supersonic collimated jets observed in young stars. Magneto-hydrodynamic processes are the most likely driving mechanism. I present the main steady and non-steady outflow models, as well as constraints brought by recent high-resolution studies. I finally discuss the origin of time variability in jets.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The internal magnetic field structure of CMEs and the field structure of the solar source regions were systematically investigated during different phases of the solar cycle in cycles 19-23 based on plasma and magnetic field measurements sampled by various satellites and through multi-wavelength remote sensing observations. It is found that: 1. To first order, the internal magnetic structure of CMEs varies systematically from one solar cycle to the next with respect to the prevailing hemispheric magnetic patterns of bipolar regions following the law of hemispheric helicity dependence. 2. To second order, the field structure in CMEs varies with respect to the complex spatial evolution of the magnetic flux in the photosphere in both hemispheres over the course of the cycle itself. The two effects can naturally explain the cyclic behavior of the SN, NS variations of the internal magnetic fields in CMEs in the solar wind as well as intermittent periods of mixed distributions.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Based on the SOHO/LASCO dataset, a collection of “structured” coronal mass ejections (CMEs) has been compiled within the period 1996-2002, in order to analyze their three-dimensional configuration. These CME events exhibit white-light fine structures, likely indicative of their possible 3D topology. From a detailed investigation of the associated low coronal and photospheric source regions, a generic scheme has been deduced, which considers the white-light topology of a CME projected in the plane of the sky as being primarily dependent on the orientation and position of the source region's neutral line on the solar disk. The obtained results imply that structured CMEs are essentially organized along a symmetry axis, in a cylindrical manner. The measured dimensions of the cylinder's base and length yield a ratio of 1.6. These CMEs seem to be better approximated by elliptic cones, rather than by the classical ice cream cone, characterized by a circular cross section.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The Geospace Double Star Project (DSP) contains two satellites operating in the near-earth equatorial and polar regions respectively. The tasks of DSP are: (i) to provide high-resolution field, particle and wave measurements in several important near-earth magnetosphere active regions which have not been covered by existing ISTP missions in the geospace, such as the near-earth plasma sheet and its boundary layer, the ring current, the radiation belts, the dayside magnetopause boundary layer, and the polar region; (ii) to investigate the trigger mechanisms of magnetic storms, magnetospheric substorms, and magnetospheric particle storms, as well as the responses of geospace storms to solar activities and interplanetary disturbances; (iii) to set up the models describing the spatial and temporal variations of the near-earth space environment. To complete the mission, there are eight instruments on board the equatorial satellite and the polar satellite, respectively. The orbit of the equatorial satellite with a perigee at 565.5km and an apogee at 78959.9km, and the inclination is 28.17 ; while the orbit of the polar satellite is proposed with a perigee at 700km and an apogee at 40000km, as well as an inclination about 90. The equatorial satellite has been launched successfully in December 2003. Now the equatorial satellite (TC-1) and instruments operate normally. Payloads have provided good quality of data of fields and particles. Already very good conjunction in the dayside magnetopause and magnetotail with Cluster, CME effects could be investigated. The first results of data analysis have already shown great interesting. The polar (TC-2) satellite has been launched successfully in July 2004. Now the satellite operates normally. The commissioning of the payload has started since the end of July 2004 and will be finished in the middle of Sep.2004. The instrument has been normally operation and downlink the data.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Four coronal mass ejections (CMEs) occurs successively from the solar disk near the west limb on October 26, 2003. They, together with the associated activities of the solar surface, were observed by various instruments both in space and on ground, such as the Large Angle and Spectrometric Coronagraph Experiment (LASCO), the Extreme Ultraviolet Imaging Telescope, and the Michelson Doppler Imager on board the Solar and Heliospheric Observatory, as well as the Huairou Solar Observing Station and the Big Bear Solar Observatory. These four events start with a filament eruption that manifests a two-ribbon flare in a spotless region, destroyed a helmet streamer, and give rise to an X1.2 flare in the active region AR0484. We notice that these eruptions occur either in active region, or in quiescent region, or in the region without any precursors. The time profiles of the CME (filament) heights show that the main acceleration takes place within one solar radius $(R_\odot)$ from the solar surface, and that all the CMEs almost propagate at constant speeds as they appear in the field of view of LASCO C2. We conclude that the most dynamical process of each of these CMEs happens at the altitudes lower than one $R_\odot$ from the surface. Among the four activities, the fourth one comes from AR10484 and shows the largest speed projected on the sky plane, which is about 1500 km s$^{-1}$; and the first filament shows the largest acceleration, $\sim 50$m s$^{-2}$.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We study in focus to the multi-wavelength radio spectra associated with quite strong CME events observed in the time interval of October 26–28, 2003. Using multi-wavelength observations recorded by WIND/WAVES experiment, Learmouth Spectrograph (Australian), PHOENIX-2 (Switzerland), Hiraiso (Japan), DAM/Nançay (France), Izmiran (Russia) and Huairou/NAOC (China), an analyzing of radio bursts was performed for the those events over a large coronal region across the microwave, the decimetric wavelength, the metric wavelength and even to much longer wavelength. The composite spectra indicate there were many complicated structures of radio bursts, including type II bursts, type IV bursts, type III bursts, drifting pulsation structures (DPS) and many radio fine structures (FS).To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We include gravity in a loss of equilibrium model for the initiation of coronal mass ejections (CMEs). We examine equilibria for both normal and inverse polarity and neglect the effects of current sheets. Although equilibria exist for normal polarities, in the absence of current sheets, the equilibria are unstable to horizontal perturbations. For the inverse polarity configuration, we find that gravity generally has a negligible effect if the magnetic field is strong ($>$50 G) but that it can have a significant effect if the magnetic field is weak. Specifically, if the characteristic magnetic field is less than about 6 G, no eruption occurs if the CME mass is on the order of 2 $\times 10^{16}$ gm.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

An analytical method is used to model a magnetic field distribution in the vicinity of a large interplanetary or solar flux rope. The field is a sum of the pre-existing one and an additional current-free part. An example using real data is shown.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

After a brief overview of solar energetic particle (SEP) emission from coronal mass ejection (CME) shocks, we turn to a discussion of their transport and acceleration. The high energy SEP are accelerated near the Sun, and because of their well-known source location, their transport can be modeled quantitatively to obtain precise information on the injection function (number of particles emitted vs. time), including a determination of the onset time to within 1 min. For certain events, transport modeling also indicates magnetic topology with mirroring or closed field loops. Important progress has also been made on the transport of low energy SEP from very strong events, which can display exhibit interesting saturation effects and compositional variations. The acceleration of SEP by CME-driven shocks in the interplanetary medium is attributed to diffusive shock acceleration, but the spectrum of SEP production is typically modeled empirically. Recent progress has largely focused on using detailed composition measurements to determine fractionation effects of shock acceleration and even to clarify the nature of the seed population. In particular, there are many indications that the seed population is suprathermal (pre-energized) and the injection problem is not relevant to acceleration at interplanetary CME-driven shocks. We argue that the finite time available for shock acceleration provides the best explanation of the high-energy rollover.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We have studied the magnetic helicity transport rate and the current helicity for solar active region (AR) NOAA 10488 and find a complex relationship between them. We further extend this study to a statistical one, and find that 33 among the selected 57 ARs show opposite sign for the two parameter.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

A class of large-scale magnetic compositions have been identified to be CME-prolific, which is characterized by a huge unipolar sunspot appearing in a large-scale extended bipolar region in synoptic magnetic charts. To understand the CMEs' origin and the nature of flux appearance, we scrutinize the long time-sequence of MDI magnetograms of high-resolution mode for super active region AR9236. Two types of magnetic features are clearly identified. They are moving magnetic features (MMFs) emanated radially from the penumbral boundary and emerging flux regions (EFRs) whose growing opposite polarities rotate out from the inner boundary of sunspot moat along helical paths in opposite directions. The interaction between the MMFs and EFRs often creates multi-fold magnetic neutral lines where the flare/CMEs initiated.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The very active RS CVn-type star UX Ari was observed using high-resolution echelle spectrograph attached to the 2.16m telescope of Xinglong station in Nov.-Dec. 2001 and Dec. 2002. By means of synthetic spectral subtraction method, the information about chromospheric activity of the system was obtained through several chromospheric activity indicators HeI D$_3$, NaI D$_1$D$_2$, H$_{\alpha}$, and CaII IRT lines. Based on the analysis for these activity indicators, we found that the chromospheric activity of UX Ari showed obvious orbital modulation phenomenon, and the favorite active longitudes were around the quadratures of the binary system. During the two observing runs, hot plage and very strong optical flare events were detected, which were always happened around the favorite active longitudes of the system. Moreover, they were linked with the photospheric starspots in spatial structure, and appeared just above the main starspots.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present the observational results of the solar bursts on the band of 1-80 GHz (NORH) associated with both a CME and a flare on Oct. 26 2003. This event shows two parts of radio bursts in the time profile. The first part is associated with an X1.2 flare. However, the following part seams related to both the flare and the CME, as the radio emission is enhanced while the ${\rm H}\alpha$ is decreasing. Thus, these two parts of radio bursts may originate from different physical processes, i.e., flare and CME shock. A primary study is performed on the difference between this two parts.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

On acceleration of relativistic electrons by any means, the coherent pinch effect brings the relativistic electrons together. The inclusion of a suitable number of positive ions, preferentially heavy ions would stabilize the beam. The heavy trapped nuclei would have to go with the electrons, thus acquire relativistic speeds. The electron beam may be divided into small bunches. This mechanism can accelerate positive nuclei to GeV and TeV energies during solar flares, stellar and galactic high energy events. During the acceleration of 1000 GeV electron bunches, the energy gained by trapped positive nuclei is estimated to reach 10$^{15}$ eV per nucleon. Higher energies can be achieved by head on collision as the energy gained by the target nucleus is proportional to $\gamma^{2},$ however fission reactions and very high energy gamma rays may occur. The principle of this mechanism is applied in electron-ring accelerators.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

In this presentation we determine the source regions of CMEs that were observed with SoHO/LASCO during times of solar activity maximum (Feb./Mar. 2000) and during the declining phase of the solar cycle (Nov./Dec. 2002). The CMEs were traced back onto the disk and EIT EUV images were used for identifying the sources. With the help of MDI synoptic magnetograms we follow the evolution of the photospheric magnetic flux about 24h before and 12h after the event. We find that about 87% of the identified CME source regions show small–scale flux changes before the event, usually flux emergence and/or flux disappearance. In 13% of the cases we find no signature of photospheric flux changes.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html