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A catalog of white light coronal mass ejections observed by the SOHO spacecraft
St. Cyr, O. C.; Plunkett, S. P.; Howard, R. A. +4 more
The Solar and Heliospheric Observatory (SOHO) mission's white light coronagraphs have observed nearly 7000 coronal mass ejections (CMEs) between 1996 and 2002. We have documented the measured properties of all these CMEs in an online catalog. We describe this catalog and present a summary of the statistical properties of the CMEs. The primary meas…
Global-Scale Turbulent Convection and Magnetic Dynamo Action in the Solar Envelope
Toomre, Juri; Brun, Allan Sacha; Miesch, Mark S.
The operation of the solar global dynamo appears to involve many dynamical elements, including the generation of fields by the intense turbulence of the deep convection zone, the transport of these fields into the tachocline region near the base of the convection zone, the storage and amplification of toroidal fields in the tachocline by different…
Solar chromospheric spicules from the leakage of photospheric oscillations and flows
De Pontieu, Bart; Erdélyi, Robert; James, Stewart P.
Spicules are dynamic jets propelled upwards (at speeds of ~20kms-1) from the solar `surface' (photosphere) into the magnetized low atmosphere of the Sun. They carry a mass flux of 100 times that of the solar wind into the low solar corona. With diameters close to observational limits (< 500km), spicules have been largely unexplained …
Torsional Oscillation, Meridional Flows, and Vorticity Inferred in the Upper Convection Zone of the Sun by Time-Distance Helioseismology
Zhao, Junwei; Kosovichev, Alexander G.
By applying time-distance helioseismology measurements and inversions to Solar and Heliospheric Observatory (SOHO) Michelson Doppler Imager (MDI) dynamics campaign data, we obtain synoptic maps of subsurface plasma-flow fields at a depth of 0-12 Mm for seven solar Carrington rotations, covering the years 1996-2002, from solar-activity minimum to m…
On the three-dimensional configuration of coronal mass ejections
Bothmer, V.; Cremades, H.
Coronal mass ejections (CMEs) are a direct consequence of the dynamic nature of the solar atmosphere. They represent fundamental processes in which energy is transferred from the Sun into interplanetary space, including geospace. Their origin, 3D structure and internal magnetic field configuration are to date not well understood. The SOHO spacecra…
Coronal Magnetic Field Measurements
Lin, H.; Kuhn, J. R.; Coulter, R.
A long-standing solar problem has been to measure the coronal magnetic field. We believe it determines the coronal structure and dynamics from the upper chromosphere out into the heliospheric environment. It is only recently that Zeeman splitting observations of infrared coronal emission lines have been successfully used to deduce the coronal magn…
Solar radiative output and its variability: evidence and mechanisms
Fröhlich, Claus; Lean, Judith
Electromagnetic radiation from the Sun is Earth’s primary energy source. Space-based radiometric measurements in the past two decades have begun to establish the nature, magnitude and origins of its variability. An 11-year cycle with peak-to-peak amplitude of order 0.1 % is now well established in recent total solar irradiance observations, as are…
Numerical simulation of the 12 May 1997 interplanetary CME event
Odstrcil, D.; Riley, P.; Zhao, X. P.
Numerical three-dimensional magnetohydrodynamic models are capable of predicting large-scale solar wind structures at Earth, provided that appropriate time-dependent boundary conditions are specified near the Sun. Since knowledge of such conditions is at present insufficient to directly drive the models, various approximations are used. In this pa…
A Study of the Kinematic Evolution of Coronal Mass Ejections
Zhang, J.; Howard, R. A.; Dere, K. P. +1 more
We report the kinematic properties of a set of three coronal mass ejections (CMEs) observed with the LASCO (Large Angle and Spectrometric Coronagraph) on the Solar and Heliospheric Observatory (SOHO) spacecraft, which showed characteristics of impulsive, intermediate, and gradual acceleration, respectively. The first CME had a 30 minute long fast …
Cone model for halo CMEs: Application to space weather forecasting
Xie, Hong; Ofman, Leon; Lawrence, Gareth
In this study, we present an innovative analytical method to determine the angular width and propagation orientation of halo Coronal Mass Ejections (CMEs). The relation of CME actual speed with apparent speed and its components measured at different position angle has been investigated. The present work is based on the cone model proposed by [2002…