Constraining triggering conditions and chromospheric energy deposition in solar flares

Solar flares are the most energetic magnetic events taking part in the solar atmosphere and are the main source of strong space weather events. They are driven by the magnetic field behavior in response to the work done to it at low atmospheric layers. Their global nature requires taking into account the coupled system formed by the photosphere, chromosphere and corona.

Some of the foremost open questions regarding solar flares are related to the triggering, the amount of magnetic free energy released, and the deposition in the chromosphere of down-propagating energy. In order to take steps along these questions, we will provide quantitative results from an observational perspective.

To do so we will rely on:Time sequences of spectropolarimetric observations at chromospheric and photospheric layers at high temporal cadence, high spatial resolution, and of full active regions.3D semi-empirical model atmospheres of the photosphere and chromosphere using a novel inversion method that guarantees, for the first time, the horizontal pressure balance (under magneto-hydrostatic constraints).The analysis of the time evolution of the 3D model atmosphere that are consistent with magnetic forces will allow for the characterization of the physical conditions that lead to the onset of flare activity, the characterization of the photospheric and chromospheric magnetic field change associated to the magnetic re-configuration, and the height at which the energy from the corona is deposited.