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Kinetic Physics of the Solar Corona and Solar Wind
Marsch, Eckart
Kinetic plasma physics of the solar corona and solar wind are reviewed with emphasis on the theoretical understanding of the in situ measurements of solar wind particles and waves, as well as on the remote-sensing observations of the solar corona made by means of ultraviolet spectroscopy and imaging. In order to explain coronal and interplanetary …
Modeling of Flux Rope Coronal Mass Ejections
Howard, R. A.; Vourlidas, A.; Thernisien, A. F. R.
We present a forward-modeling technique for flux rope-like CMEs using an empirically defined model of a flux rope, the graduated cylindrical shell (GCS). To compare it with white-light coronagraph observations, we assume an electron distribution through the GCS and derive synthetic images in total and polarized brightness for various projections o…
A Statistical Study of Main and Residual Accelerations of Coronal Mass Ejections
Zhang, J.; Dere, K. P.
In this paper we present the results of a statistical study of the accelerations of coronal mass ejections (CMEs). A CME usually undergoes a multiphased kinematic evolution, with a main acceleration phase characterized by a rapid increase of CME velocity in the inner corona, followed by a relatively smooth propagation phase characterized by a cons…
Solar Differential Rotation Influenced by Latitudinal Entropy Variations in the Tachocline
Toomre, Juri; Brun, Allan Sacha; Miesch, Mark S.
Three-dimensional simulations of solar convection in spherical shells are used to evaluate the differential rotation that results as thermal boundary conditions are varied. In some simulations a latitudinal entropy variation is imposed at the lower boundary in order to take into account the coupling between the convective envelope and the radiativ…
Variations in solar luminosity and their effect on the Earth's climate
Fröhlich, C.; Foukal, P.; Spruit, H. +1 more
Variations in the Sun's total energy output (luminosity) are caused by changing dark (sunspot) and bright structures on the solar disk during the 11-year sunspot cycle. The variations measured from spacecraft since 1978 are too small to have contributed appreciably to accelerated global warming over the past 30 years. In this Review, we show that …
A Model for Spectral and Compositional Variability at High Energies in Large, Gradual Solar Particle Events
Lee, Martin A.; Tylka, Allan J.
Shocks driven by fast coronal mass ejections (CMEs) are generally believed to be the dominant accelerators in large, gradual solar energetic particle (SEP) events. A key challenge for this notion has been the highly variable spectral and compositional characteristics of these events above a few tens of MeV per nucleon. We have recently proposed th…
Magnetoacoustic Portals and the Basal Heating of the Solar Chromosphere
McIntosh, Scott W.; Cacciani, Alessandro; Armstrong, James D. +3 more
We show that inclined magnetic field lines at the boundaries of large-scale convective cells (supergranules) provide ``portals'' through which low-frequency (<5 mHz) magnetoacoustic waves can propagate into the solar chromosphere. The energy flux carried by these waves at a height of 400 km above the solar surface is found to be a factor of 4 g…
The Proper Treatment of Coronal Mass Ejection Brightness: A New Methodology and Implications for Observations
Vourlidas, Angelos; Howard, Russell A.
With the complement of coronagraphs and imagers in the SECCHI suite, we will follow a coronal mass ejection (CME) continuously from the Sun to Earth for the first time. The comparison, however, of the CME emission among the various instruments is not as easy as one might think. This is because the telescopes record the Thomson-scattered emission f…
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…
Ultraviolet spectroscopy of the extended solar corona
Kohl, John L.; Noci, Giancarlo; Cranmer, Steven R. +1 more
The first observations of ultraviolet spectral line profiles and intensities from the extended solar corona (i.e., more than 1.5 solar radii from Sun-center) were obtained on 13 April 1979 when a rocket-borne ultraviolet coronagraph spectrometer of the Harvard-Smithsonian Center for Astrophysics made direct measurements of proton kinetic temperatu…