Search Publications
Remote and in situ observations of an unusual Earth-directed coronal mass ejection from multiple viewpoints
Anderson, B. J.; Szabo, A.; Nieves-Chinchilla, T. +5 more
During June 16-21, 2010, an Earth-directed coronal mass ejection (CME) event was observed by instruments onboard STEREO, SOHO, MESSENGER and Wind. This event was the first direct detection of a rotating CME in the middle and outer corona. Here, we carry out a comprehensive analysis of the evolution of the CME in the interplanetary medium comparing…
Global network of slow solar wind
Crooker, N. U.; Neugebauer, M.; Antiochos, S. K. +1 more
The streamer belt region surrounding the heliospheric current sheet (HCS) is generally treated as the primary or sole source of the slow solar wind. Synoptic maps of solar wind speed predicted by the Wang-Sheeley-Arge model during selected periods of solar cycle 23, however, show many areas of slow wind displaced from the streamer belt. These area…
Cyclic loss of open solar flux since 1868: The link to heliospheric current sheet tilt and implications for the Maunder Minimum
Owens, M. J.; Lockwood, M.
Open solar flux (OSF) variations can be described by the imbalance between source and loss terms. We use spacecraft and geomagnetic observations of OSF from 1868 to present and assume the OSF source, S, varies with the observed sunspot number, R. Computing the required fractional OSF loss, χ, reveals a clear solar cycle variation, in approximate p…
Time-dependent MHD modeling of the global solar corona for year 2007: Driven by daily-updated magnetic field synoptic data
Liu, Yang; Wu, S. T.; Feng, X. S. +3 more
In this paper, we develop a time-dependent MHD model driven by the daily-updated synoptic magnetograms (MHD-DUSM) to study the dynamic evolution of the global corona with the help of the 3D Solar-Interplanetary (SIP) adaptive mesh refinement (AMR) space-time conservation element and solution element (CESE) MHD model (SIP-AMR-CESE MHD Model). To ac…
The discrepancy in solar EUV-proxy correlations on solar cycle and solar rotation timescales and its manifestation in the ionosphere
Liu, Libo; Wan, Weixing; Chen, Yiding
This study investigates the correlations between SOHO/Solar EUV Monitor 26-34 nm EUV and the F10.7 and Mg II proxies on solar cycle (long-term) and solar rotation (short-term) timescales. The long-term components of EUV and proxies are well correlated, and the general relation between them can be captured by the 81 day averaged EUV and …
Dependence of solar proton events on their associated activities: Coronal mass ejection parameters
Moon, Y. -J.; Gopalswamy, N.; Park, J.
In this study we have examined the occurrence probability of solar proton events (SPEs) and their peak fluxes depending on coronal mass ejection (CME) parameters, linear speed (V), angular width (AW), and location (L). For this we used the NOAA SPE list and their associated CME data from 1997 to 2006. We found that the probability strongly depends…
Formation, shape, and evolution of magnetic structures in CIRs at 1 AU
McComas, D. J.; Desai, M. I.; Broiles, T. W.
We have surveyed the properties of 153 co-rotating interaction regions (CIRs) observed at 1 AU from January, 1995 through December, 2008. We identified that 74 of the 153 CIRs contain planar magnetic structures (PMSs). For planar and non-planar CIRs, we compared distributions of the bulk plasma and magnetic field parameters. Our identification of …
An analysis of thermospheric density response to solar flares during 2001-2006
Le, Huijun; Liu, Libo; Wan, Weixing
Previous studies show there are significant thermospheric responses to the two great solar flares on October 28, 2003 (X17.2) and November 4, 2003 (X28). In the present study, we further explored the thermospheric response to all X-class solar flares during 2001-2006. The observed results show that X5 and stronger solar flares can induce an averag…
Radio-loud CMEs from the disk center lacking shocks at 1 AU
MacDowall, R. J.; Kaiser, M. L.; Gopalswamy, N. +4 more
A coronal mass ejection (CME) associated with a type II burst and originating close to the center of the solar disk typically results in a shock at Earth in 2-3 days and hence can be used to predict shock arrival at Earth. However, a significant fraction (about 28%) of such CMEs producing type II bursts were not associated with shocks at Earth. We…
Understanding shock dynamics in the inner heliosphere with modeling and Type II radio data: The 2010-04-03 event
St. Cyr, O. C.; Odstrcil, D.; Gopalswamy, N. +3 more
The 2010 April 03 solar event was studied using observations from STEREO SECCHI, SOHO LASCO, and Wind kilometric Type II data (kmTII) combined with WSA-Cone-ENLIL model simulations performed at the Community Coordinated Modeling Center (CCMC). In particular, we identified the origin of the coronal mass ejection (CME) using STEREO EUVI and SOHO EIT…