8 research outputs found
Magnetic nulls and super-radial expansion in the solar corona
Magnetic fields in the sun's outer atmosphere -- the corona -- control both
solar-wind acceleration and the dynamics of solar eruptions. We present the
first clear observational evidence of coronal magnetic nulls in off-limb
linearly polarized observations of pseudostreamers, taken by the Coronal
Multichannel Polarimeter (CoMP) telescope. These nulls represent regions where
magnetic reconnection is likely to act as a catalyst for solar activity. CoMP
linear-polarization observations also provide an independent, coronal proxy for
magnetic expansion into the solar wind, a quantity often used to parameterize
and predict the solar wind speed at Earth. We introduce a new method for
explicitly calculating expansion factors from CoMP coronal linear-polarization
observations, which does not require photospheric extrapolations. We conclude
that linearly-polarized light is a powerful new diagnostic of critical coronal
magnetic topologies and the expanding magnetic flux tubes that channel the
solar wind
Existence of two MHD reconnection modes in a solar 3D magnetic null point topology
International audienc
Existence of two MHD reconnection modes in a solar 3D magnetic null point topology
International audienc
Existence of two MHD reconnection modes in a solar 3D magnetic null point topology
International audienc
Coronal jets in an inclined coronal magnetic field : a parametric 3D MHD study
International audienceX-ray solar coronal jets are short-duration, fast, well collimated plasma brightenings occurring in the solar corona. To explain and understand the processes driving the jets, one must be able to model an explosive release of free energy. Magnetic reconnection is believed to play a key role in the generation of these energetic bursting events. The model of jets that we have been developing is based on a magnetic field constructed by embedding a vertical magnetic dipole in a uniform open magnetic field. In this study, we investigate the influence of the inclination of the open field on the properties of the jet using numerical simulations. We will show that the inclination of the open field is of critical importance for the properties of the jet such as the energy released. We conclude that the characteristics of the open field at the time of observations are a central criterion that must be taken into account and reported on in observational studies