The solar wind carries magnetic flux from the photosphere into the heliosphere, making it topologically open in the corona. Open magnetic flux is unevenly distributed at the solar surface, but at some distance in the outer corona it becomes uniformly distributed and approximately radial. Standard potential field models do not provide such uniform distribution of open flux in the heliosphere. A ...

The existence of power law statistics in solar and stellar flares has prompted the suggestion that solar and stellar coronae are in a self-organized critical state, but the physical foundation of this theory is lacking. We present observational evidence from 107 flare events in 37 sun-like stars that solar and stellar coronae self-organize into a critical state set by a bifurcation in the dynam...

We present in this Letter the first coordinated radio occultation measurements and ultraviolet observations of the inner corona below 5.5 R,, obtained during the Galileo solar conjunction in January 1997, to establish the origin of the slow solar ~vind. Limits on the flow speed are derived from the Doppler dimming of the resonantly scattered component of the oxygen 1032 and 1037 ~ lines as meas...

Previous theoretical work suggests that magnetic reconnection in the solar corona should occur along particular topological boundaries in the coronal magnetic Ðeld known as separators. Thus, a ÐeldÏs topological structure predicts the locations of X-ray/EUV loops, assuming enhanced emission is related to reconnection. We use this topological model in a theoretical study of the statistical prope...

We present in this Letter the first coordinated radio occultation measurements and ultraviolet observations of the inner corona below 5.5 Rs, obtained during the Galileo solar conjunction in January 1997, to establish the origin of the slow solar wind. Limits on the flow speed are derived from the Doppler dimming of the resonantly scattered component of the oxygen 1032 Å and 1037 Å lines as mea...

In this paper we carry out numerical modeling of coronal jets to understand their effects on the global corona and their contribution to the solar wind. We simulated jet models implemented within a well established three dimensional, two-temperature magneto-hydrodynamic (MHD) solar corona model that is built upon kinetic Alvén wave dissipation, producing realistic solar wind background. The jet...

High-cadence, high-resolution magnetograms have shown that the quiet-Sun photosphere is very dynamic in nature. It is comprised of discrete magnetic fragments which are characterized by four key processes – emergence, coalescence, fragmentation and cancellation. All of this will have consequences for the magnetic field in the corona above. The aim of this study is to gauge the effect of the beh...

It is clear that the solar corona is being heated and that coronal magnetic fields undergo reconnection all the time. Here we attempt to show that these two facts are related--i.e. coronal reconnection generates heat. This attempt must address the fact that topological change of field lines does not automatically generate heat. We present one case of flux emergence where we have measured the ra...

The atmospheric corona is a well-known diffraction phenomenon, typically seen as colored rings surrounding the Sun or Moon. In many respects, Fraunhofer diffraction provides a good explanation of the corona. As the angular sizes of the corona's rings are inversely proportional to the radius, r, of the spherical particles causing the corona, it should be easy to estimate the particle size from o...

The magnetic field of the Sun and the plasma properties of its atmosphere, such as temperature distribution, density stratification, photospheric convection and waves in the corona, determine the origin, energetics and evolution of the solar wind. The solar wind comes in three main kinds, as steady fast streams, variable slow flows and transient slow and fast coronal mass ejections. The three t...