Search Publications
Solar activity variations of the ionospheric peak electron density
Liu, Libo; Wan, Weixing; Ning, Baiqi +2 more
The daily averaged Solar EUV Monitor (SEM)/Solar Heliospheric Observatory (SOHO) EUV measurements, solar proxies, and foF2 data at 20 ionosonde stations in the east Asia/Australia sector are collected to investigate the solar activity dependences of the ionospheric peak electron density (NmF2). The intensities of solar EUV from the SEM/SOHO measur…
Coronal prominence structure and dynamics: A magnetic flux rope interpretation
Gibson, S. E.; Fan, Y.
The solar prominence is an example of a space physics phenomenon that can be modeled as a twisted magnetic flux tube or magnetic flux "rope." In such models the prominence is one observable part of a larger magnetic structure capable of storing magnetic energy to drive eruptions. We show how a flux rope model explains a range of observations of pr…
Coronal mass ejections and magnetic flux buildup in the heliosphere
Owens, M. J.; Crooker, N. U.
To test for magnetic flux buildup in the heliosphere from coronal mass ejections (CMEs), we simulate heliospheric flux as a constant background open flux with a time-varying interplanetary CME (ICME) contribution. As flux carried by ejecta can only contribute to the heliospheric flux budget while it remains closed, the ICME flux opening rate is an…
Long-lived geomagnetic storms and coronal mass ejections
Gopalswamy, N.; Yashiro, S.; Lara, A. +3 more
Coronal mass ejections (CMEs) are major solar events that are known to cause large geomagnetic storms (Dst < -100 nT). Isolated geomagnetic storms typically have a main phase of 3-12 hours and a recovery phase of around 1 day. However, there are some storms with main and recovery phases exceeding ∼3 days. We trace the origin of these long-lived…
Solar Mass Ejection Imager (SMEI) observations of coronal mass ejections (CMEs) in the heliosphere
Price, S.; Simnett, G. M.; Webb, D. F. +16 more
The Solar Mass Ejection Imager (SMEI) on the Coriolis spacecraft has been obtaining white light images of nearly the full sky every 102 minutes for three years. We present statistical results of analysis of the SMEI observations of coronal mass ejections (CMEs) traveling through the inner heliosphere; 139 CMEs were observed during the first 1.5 ye…
Interplanetary hydrogen absolute ionization rates: Retrieving the solar wind mass flux latitude and cycle dependence with SWAN/SOHO maps
Bertaux, Jean-Loup; Lallement, Rosine; Schmidt, Walter +4 more
We present results of the total hydrogen ionization rate obtained from the inversion of almost 10 years of full-sky maps of the interplanetary Lyman α background measured by the SWAN instrument on SOHO. Thanks to a new estimate of the absolute calibration of the SWAN instrument and its variation during the 10 years of operation of SOHO, we are abl…
Are halo coronal mass ejections special events?
Gopalswamy, Nat; Xie, Hong; Lara, Alejandro +3 more
We revisited the properties of wide coronal mass ejections (CMEs) called halo CMEs. Using the large LASCO/SOHO CMEs data set, from 1996 to 2004, we examined the statistical properties of (partial and full) halo CMEs and compare with the same properties of "normal" width (lower than 120°) CMEs. We found that halo CMEs have different properties than…
The 17-22 October (1999) solar-interplanetary-geomagnetic event: Very intense geomagnetic storm associated with a pressure balance between interplanetary coronal mass ejection and a high-speed stream
Balmaceda, Laura A.; Dal Lago, Alisson; Gonzalez, Walter D. +9 more
Using observations from the Advanced Composition Explorer (ACE) magnetic field and plasma experiments, we investigate the magnetic, thermal, and dynamic pressure balance in the border of a high-speed stream (HSS) and an average-speed interplanetary coronal mass ejection (ICME) observed on 21-22 October (1999). We believe that the HSS compressed th…
Success rate of predicting the heliospheric magnetic field polarity with Michelson Doppler Imager (MDI) synoptic charts
Liu, Y.; Hoeksema, J. T.; Scherrer, P. H. +1 more
The photospheric and heliospheric magnetic fields have been continuously observed at the L1 point by the Michelson Doppler Imager (MDI) on the Solar and Heliospheric Observatory (SOHO) and Wind and the Advanced Composition Explorer (ACE) spacecraft since 1996. The combined observations of the photospheric and heliospheric magnetic fields make it p…
A global 2.5-dimensional three fluid solar wind model with alpha particles
Li, Xing; Li, Bo; Labrosse, Nicolas
A global 2.5-dimensional three fluid solar wind model is presented. Two ion species, namely protons and alpha particles, are heated by an empirical energy flux while electrons are heated by the classical heat flux and Coulomb coupling with ions. It is found that for a reasonable relative speed between alpha particles and protons at 1 AU to be achi…