Search Publications
Minute pulsations in microwaves and X-rays during the flare on May 6, 2005
Kupriyanova, E. G.; Ratcliffe, H.
Quasi-periodic pulsations are a common feature in the emission associated with solar flares. In particular, pulsations with periods of tens of seconds to a few minutes are often seen in microwave and hard X-ray emission. We examine the spatial and temporal structure of the emission during the flare on May 6, 2005. The source of the flare is a magn…
Phase relations between total solar irradiance and the Mg II index
Li, K. J.; Xu, J. C.; Feng, W. +1 more
The Mg II index is usually used to represent the brightening contribution to total solar irradiance (TSI) by solar bright structures, such as faculae and network. In order to understand variations of TSI, phase relations of TSI and the chromospheric Mg II index is investigated on time-scales of one year and longer. The NOAA daily Mg II index at th…
Coronal partings
Dumin, Yurii V.; Nikulin, Igor F.
The basic observational properties of "coronal partings"-the special type of quasi-one-dimensional magnetic structures, identified by a comparison of the coronal X-ray and EUV images with solar magnetograms-are investigated. They represent the channels of opposite polarity inside the unipolar large-scale magnetic fields, formed by the rows of magn…
Development of a formalism for computing transits of Earth-directed CMEs, plasma sheaths, and shocks. Towards a forecasting tool
Corona-Romero, P.; Gonzalez-Esparza, J. A.
Interplanetary Coronal mass ejections (ICMEs) (super-magnetosonically) faster than the ambient solar wind are preceded by shock waves. Earth-directed shock waves, plasma sheaths and ICMEs are precursors of the major geomagnetic storms. The plasma sheath between the shock and the ICME leading edge plays a very important role to determine the geoeff…
Relationship between magnetic field properties and an X-class flare in active region NOAA 9077
Liu, D.; Liu, S.
The magnetic field plays a key role in producing solar flares, so that the investigation on the relationship between the magnetic field properties and flares is significant. In this paper, based on the magnetic field extrapolated from the photospheric vector magnetograms of the active region NOAA 9077 obtained at Huairou Solar Observing Station, t…
The number distribution of weak Explosive Events observed by SUMER/SoHO
Mendoza-Torres, J. E.
Explosive Events (EEs) observed by SUMER on SoHO at the 1393.8 Å Si IV line are analyzed. We look for EEs to study their number distribution at low energies. Eight data sets taken in June 1996 in raster observations are used. In these observations a field on the solar disk is scanned several times during a period considerably longer than the typic…
Possible signature of solar oblateness in the Sun's oscillation frequency splittings
Woodard, M. F.
Departures from spherical symmetry split the frequencies of the Sun's normal oscillation modes. In addition to the well-studied, dominant splitting of the mode frequencies, due to the first-order advection of internal wave motion, a number of second-order effects of rotation on the frequency splittings, predominantly the solar oblateness, are expe…