Reconstruction of the Parker spiral with the Reverse In situ data and MHD APproach – RIMAP

Abstract

The reconstruction of plasma parameters in the interplanetary medium is very important to understand the interplanetary propagation of solar eruptions and for Space Weather application purposes. Because only a few spacecraft are measuring in situ these parameters, reconstructions are currently performed by running complex numerical Magneto-hydrodynamic (MHD) simulations starting from remote sensing observations of the Sun. Current models apply full 3D MHD simulations of the corona or extrapolations of photospheric magnetic fields combined with and semiempirical relationships to derive the plasma parameters on a sphere centered on the Sun (inner boundary). The plasma is then propagated in the interplanetary medium up to the Earth’s orbit and beyond. Nevertheless, this approach requires significant theoretical and computational efforts, and the results are only in partial agreement with the in situ observations. In this paper we describe a new approach to this problem called RIMAP - Reverse In situ data and MHD APproach. The plasma parameters in the inner boundary at 0.1 AU are derived directly from the in situ measurements acquired at 1 AU, by applying a back reconstruction technique to remap them into the inner heliosphere. This remapping is done by using the Weber and Davies solar wind theoretical model to reconstruct the wind flowlines. The plasma is then re-propagated outward from 0.1 AU by running a MHD numerical simulation based on the PLUTO code. The interplanetary spiral reconstructions obtained with RIMAP are not only in a much better agreement with the in situ observations, but are also including many more small-scale longitudinal features in the plasma parameters that are not reproduced with the approaches developed so far.

Tracing the ICME plasma with a MHD simulation

“…The background condition of the interplanetary Parker spiral for the ICME simulation is reconstructed by RIMAP using plasma parameters measured by Wind in 2009 between March 3 and March 29 (Biondo et al 2021), around the minimum of solar activity cycle 23. Even if this time frame was chosen due to its relatively calm solar wind conditions, the RIMAP-reconstructed Parker spiral is highly structured in its longitudinal variability (Fig.…”

Connecting Solar Orbiter remote-sensing observations and Parker Solar Probe in situ measurements with a numerical MHD reconstruction of the Parker spiral

“…The additional UV channel correction steps, such as the correction of the spatial response disuniformity, were performed according to Andretta et al (2021). RIMAP (Biondo et al 2021a) is a technique for reconstructing the Parker spiral on the equatorial plane, starting from an analytically built inner boundary and propagating it outwards by solving the time-dependent magnetohydrodynamics (MHD) equations in a frame corotating with the solar equator. This approach was shown to reproduce the fine longitudinal structure of the spiral and to accurately match the features mea-sured at 1 AU.…”

“…All these previous works made various assumptions to reconstruct the path followed by the solar plasma propagating from the inner corona to the interplanetary medium. The goal of the present work is to accurately reconstruct the Parker spiral and to connect the coronal features observed remotely by the Metis coronagraph (Antonucci et al 2020) on board Solar Orbiter with those detected in situ by PSP, at the time of the first PSP-Solar Orbiter quadrature which occurred on January 2021 , by using the Reverse In-situ and Magnetohydrodynamics APproach (RIMAP, Biondo et al 2021a), a hybrid analytical-numerical method for reconstructing the Parker spiral.…”

Stream-Aligned Magnetohydrodynamics for Solar Wind Simulations

“…For space weather applications (see, e.g. Biondo, Ruggero et al 2021, relating the properties of the solar wind in situ with the remotely observed structure of the solar corona, by tracing the stream-line in co-rotating frame from the observation point toward its origin site) this is a large difference, meaning that field line associated phenomena (like SEP events) will arrive to Earth some 15 hours later than predicted by Parker (1958) spiral connectivity models. It is important, therefore, that our computational model fully incorporates all principles and opportunities of the earlier models.…”