Solar activity and its evolution across the corona: recent advances

Abstract

Solar magnetism is responsible for the several active phenomena that occur in the solar atmosphere. The consequences of these phenomena on the solar-terrestrial environment and on Space Weather are nowadays clearly recognized, even if not yet fully understood. In order to shed light on the mechanisms that are at the basis of the Space Weather, it is necessary to investigate the sequence of phenomena starting in the solar atmosphere and developing across the outer layers of the Sun and along the path from the Sun to the Earth. This goal can be reached by a combined multi-disciplinary, multi-instrument, multi-wavelength study of these phenomena, starting with the very first manifestation of solar active region formation and evolution, followed by explosive phenomena (i.e., flares, erupting prominences, coronal mass ejections), and ending with the interaction of plasma magnetized clouds expelled from the Sun with the interplanetary magnetic field and medium. This wide field of research constitutes one of the main aims of COST Action ES0803: Developing Space Weather products and services in Europe. In particular, one of the tasks of this COST Action was to investigate the Progress in Scientific Understanding of Space Weather. In this paper we review the state of the art of our comprehension of some phenomena that, in the scenario outlined above, might have a role on Space Weather, focusing on the researches, thematic reviews, and main results obtained during the COST Action ES0803.

Supergranular-scale magnetic flux emergence beneath an unstable filament

“…The breakout model (Antiochos 1998;Antiochos et al 1999) depends on significant shearing, and involving reconnection above the flux rope (Schmieder et al 2013). Reconnection is strongly enclosed in some of these models (Zuccarello et al 2013). Loss of equilibrium models (Forbes & Isenberg 1991;Forbes & Priest 1995) may explain the slow filament rising (Schmieder et al 2013).…”

What characterizes planetary space weather?

“…A recent review has been published that makes a full description of the different facets of the Sun that are relevant for terrestrial space weather (Zuccarello et al 2013). In the following, we will briefly summarize the most important features.…”

Comparison of Magnetohydrodynamics Simulation And Observasional Result to Solar Coronal Helmet Streamer

“…They are usually situated above active regions or above remnant of old active regions [1]. These helmet streamers can be seen in white light because the electron density are about ten times higher than in the quiet corona (see fig.…”

“…Despite plasma having similar properties as a gas, it may form structures such as filaments, beams and double layers when in the presence of a magnetic field [1]. The presence of a charge non-negligible carriers makes the plasma electrically conductive so that it responds strongly to electromagnetic fields.…”

“…The coronal plasma density distribution is not isotropic as a result of the penetration by the helmet streamer magnetic structure [1,3,4]. Figure 1 is making image of the process white light data with several helmet streamers structure (A and B) [2,3].…”