Periodic Reporting for period 3 - WHOLE SUN (The Whole Sun Project: Untangling the complex physical mechanisms behind our eruptive star and its twins)
Periodo di rendicontazione: 2022-05-01 al 2023-10-31
The aim of the Whole Sun project is to understand the nature of the activity of our star, the Sun, as a whole. Typically, during the past few decades, solar physics research was focused towards studying the structure and dynamics of either the solar interior or of the solar surface/atmosphere. Our goal is to consolidate studies of these two broad solar regions, through strong synergies between the team members, in order to gain an advanced understanding of their coupling and of the Sun. The detailed study of the (thermo)dynamical and magnetic coupling between the deep solar interior, the solar surface and the highly-stratified atmosphere is absolutely essential if one wants to address key open problems in solar physics.
We have gathered a team of European world leaders in solar physics, stellar physics, and computational astrophysics to tackle all facets of our complex star: from deep inside where the magnetic field originates through dynamo action to surface convection where the field emerges and erupts to the extended atmosphere where the fields expand, heat the corona and propel the solar wind. For the first-time experts in all aspects required to understand our star and its nonlinear dynamics will be working together in a synergistic way to tackle a question that seems so obvious but has been eluding a clear answer for more than one century: How does the magnetic Sun work as a whole and evolve?
For too long solar physics has been split in sub domains, below and above the solar surface (photosphere), lacking this global and integrated view that the Whole Sun Project is proposing as its pivotal, essential and constitutive fundament. We wish to study at the most fundamental and ab-initio level, yet retaining a high level of realism in modelling our star, the complex and nonlinear physical mechanisms at play in our star, developing for this ambitious goal a framework to integrate all the recent advances that the community and the PI’s of the project have brought to understand the Sun.
The impact of our active Sun on Earth and our technological society is key to characterise and understand in order to mitigate the negative impact it could have during strong activity events. Our work on the ab-initio fundamental understanding of the Sun, will help improving our forecasting skills of the solar activity and hence will directly serve our modern society by helping mitigate its impact on our various infrastructures (power grid, satellites, communications,….).
We have gathered a team of European world leaders in solar physics, stellar physics, and computational astrophysics to tackle all facets of our complex star: from deep inside where the magnetic field originates through dynamo action to surface convection where the field emerges and erupts to the extended atmosphere where the fields expand, heat the corona and propel the solar wind. For the first-time experts in all aspects required to understand our star and its nonlinear dynamics will be working together in a synergistic way to tackle a question that seems so obvious but has been eluding a clear answer for more than one century: How does the magnetic Sun work as a whole and evolve?
For too long solar physics has been split in sub domains, below and above the solar surface (photosphere), lacking this global and integrated view that the Whole Sun Project is proposing as its pivotal, essential and constitutive fundament. We wish to study at the most fundamental and ab-initio level, yet retaining a high level of realism in modelling our star, the complex and nonlinear physical mechanisms at play in our star, developing for this ambitious goal a framework to integrate all the recent advances that the community and the PI’s of the project have brought to understand the Sun.
The impact of our active Sun on Earth and our technological society is key to characterise and understand in order to mitigate the negative impact it could have during strong activity events. Our work on the ab-initio fundamental understanding of the Sun, will help improving our forecasting skills of the solar activity and hence will directly serve our modern society by helping mitigate its impact on our various infrastructures (power grid, satellites, communications,….).
We have made key progress in the various work packages of the Whole Sun project. We have been able to detect, model and characterize inertial modes in the Sun, perform seismic sounding of flux emergence and large scale flow simulations and compare them to helioseismic inversions, develop new more realistic global solar convection and dynamo simulations, couple local and global solar MHD codes for improving the realism of our 3D MHD simulations, assess energy and Poynting flow transfers from the convective envelope into the low atmosphere, carry out a large-box computation including a deep convective layer and extensive atmosphere, model large-amplitude oscillations in prominences triggered by coronal jets. We have also made a significant step forward at developing the next generation solar physics code. We are currently following 2 complementary paths, one based on a block-based AMR multi-regime code (Dyablo-Whole Sun) and another based on a multi-purpose framework called Dispatch that we are adapting to include Bifrost solver and realistic physics.
Coupling dynamically internal and external solar dynamics is very challenging and we have made key steps forward in such direction.
We have for instance been able to couple a solar dynamo to a solar wind solution and see how new more complex boundary conditions can jointly impact the wind and dynamo solutions.
We have also started to couple global dynamo code such as ASH to local Cartesian codes such as Lare3D or Bifrost.
We are further developing new solar physics codes that will include the advantage of a global code with that of the detailed physics and dynamics of a local code in a coherent whole using a block-based AMR multi-regime MHD hybrid (cpus/gpus/ARM) with radiative transfer approach. We have now a working MHD version and are developing spherical versions.
The main goal of Whole Sun is to be able to follow on short (hours/days) and long (years/decade) time scales the complex multi-regime magnetohydrodynamics of our star the Sun and by extension solar analogues. Thanks to a modular approach the new code will allow us to turn on or off various physical mechanisms in order to make the simulations advanced at various speed depending on what we wish to study, for instance cyclic activity and the effective role of active regions or a specific transient flux emergence event driven self-consistently by the dynamo that can further erupt and eject a plasmoid into the atmosphere and its associated multi-wavelength emission signatures. Such results will allow us to model our Sun in a “Sun in time” approach, where the evolution of the internal structure, mass content, rotation rate and magnetic and eruptivity levels will be followed with an accuracy and realism never realized before.
We have for instance been able to couple a solar dynamo to a solar wind solution and see how new more complex boundary conditions can jointly impact the wind and dynamo solutions.
We have also started to couple global dynamo code such as ASH to local Cartesian codes such as Lare3D or Bifrost.
We are further developing new solar physics codes that will include the advantage of a global code with that of the detailed physics and dynamics of a local code in a coherent whole using a block-based AMR multi-regime MHD hybrid (cpus/gpus/ARM) with radiative transfer approach. We have now a working MHD version and are developing spherical versions.
The main goal of Whole Sun is to be able to follow on short (hours/days) and long (years/decade) time scales the complex multi-regime magnetohydrodynamics of our star the Sun and by extension solar analogues. Thanks to a modular approach the new code will allow us to turn on or off various physical mechanisms in order to make the simulations advanced at various speed depending on what we wish to study, for instance cyclic activity and the effective role of active regions or a specific transient flux emergence event driven self-consistently by the dynamo that can further erupt and eject a plasmoid into the atmosphere and its associated multi-wavelength emission signatures. Such results will allow us to model our Sun in a “Sun in time” approach, where the evolution of the internal structure, mass content, rotation rate and magnetic and eruptivity levels will be followed with an accuracy and realism never realized before.