coupling solar simulations with space weather: code...
TRANSCRIPT
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Coupling Solar Simulations with Space Weather: Code Comparison in SWIFF Consortium
Vyacheslav Olshevsky
1Center for Plasma Astrophysics, Mathematics Department, KU Leuven 2Main Astronomical Observatory, Kyiv, Ukraine [email protected] Co-authors: Anna Lisa Restante1, Giovanni Lapenta1 and Rony Keppens1
mailto:[email protected]
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Introduction
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SWIFF – Space Weather Integrated Forecasting Framework. The principal goal of SWIFF is development of mathematical models and computational methods to handle multiple physics and multiple scales of space weather.
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Multi-physics in space weather
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Multi-scale in space weather
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Participants
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5 scientific and 1 management work packages (WPs):
• WP1. Coordination: Giovanni Lapenta, Katholieke Universiteit Leuven (KU Leuven, Belgium)
• WP2. Multiscale-Multiphysics Modelling: Rony Keppens, Katholieke Universiteit Leuven (KU Leuven, Belgium)
• WP3. Coupling at the Sun: Åke Nordlund, University of Copenhagen (UCPH, Denmark)
• WP4. Coupling in space: Francesco Califano, Università di Pisa (UNIPISA, Italy)
• WP5. Coupling at the Earth: Viviene Pierrard, Belgian Institute for Space Aeronomy (BISA, Belgium)
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20.06.2012 First results of SWIFF 6
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Numerical Codes
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• FlipMHD – viscous resistive MHD code (Brackbill, 1991)
• MPI-AMRVAC – MPI implementation of the Versatile Advection Code with adaptive Mesh Refinement (Keppens et al 2012)
• iPic3D (KU Leuven) • Stagger (UCPH, Denmark) • UNIPI two-fluid code • ASI hybrid PIC code
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Benchmarks
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• Transition to turbulent reconnection (2D)
• Longcope-Strauss problem (2D)
• Magnetopause challenge (2D)
• CME initiation challenge (3D)
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Flux Rope Emergence Setup
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𝑩 = 𝜵 ×𝐴 𝑟, 𝜃𝑟 sin𝜃
𝜑� + 𝐵𝜑 𝑟,𝜃 𝜑� ,
A 𝑟,𝜃 = 12𝑞𝑎2𝐵𝑡exp −
𝜔�2 𝑟,𝜃𝑎2
,
𝐵𝜑 𝑟,𝜃 =𝑎𝐵𝑡𝑟 sin𝜃
exp −𝜔�2 𝑟,𝜃𝑎2
.
Semi-circular rope (Fan & Gibson 2004)
Embedded to the background sheared arcade (Aschwanden 2004)
𝐵𝑥 = 𝐵𝑥0 sin 𝑘𝑘 exp −𝑙𝑙 , 𝐵𝑦 = 𝐵𝑦0 sin 𝑘𝑘 exp −𝑙𝑙 , 𝐵𝑧 = 𝐵𝑧0 cos 𝑘𝑘 −𝑙𝑙 ,
𝐵𝑥0 =𝑙𝑘𝐵0,𝐵𝑦0 =
𝛼𝑘𝐵0, 𝑘2 − 𝑙2 − 𝛼2 = 0.
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Setup Parameters
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𝐵0 = 𝑝0 = 𝜌0 = 1, 𝑢0 = 0, 𝐵𝑡 = 9𝐵0, 𝑅 = 0.375, 𝑞 = −1, 𝑎 = 0.1, 𝐿𝑥 = 1.5, 𝐿𝑦 = 1, 𝐿𝑧 = 1.25, 𝑛𝑥 = 30,𝑛𝑦 = 20,𝑛𝑧 = 25.
Boundary conditions: X – open Y – periodic Top – open Bottom – constant Bz
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Results: FlipMHD
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Viscous No viscosity
Blue represent magnetic field lines; red contour is at constant density 0.8; The grayscale on the bottom is Bz. Note the destruction of density “tube” in the second case!
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FlipMHD vs MPI-AMRVAC
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FlipMHD (no viscosity) MPI-AMRVAC
Blue represent magnetic field lines; red contour is at constant density 0.8; The grayscale on the bottom is Bz. In both cases, the tube is destroyed. The behavior of field lines is very similar.
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Density Variation in XZ Plane
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Results: rise of the rope
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Conclusions
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The initial configuration leads to immediate emergence of the flux rope, and is handy for comparison of numerical codes The overall behavior is qualitatively the same in FlipMHD and MPI-AMRVAC simulations Rise and rotation of the flux rope is faster in the simulations of MPI-AMRVAC
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Future? Particle-in-cell (PIC)
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Equations of implicit moment PIC
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Equations of motion (moments of Vlasov)
Interpolation of fields to particles
Coupling of fields and particles is nonlinear:
Markidis, Lapenta, Rizwan-uddin (2010), Lapenta (2012)
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iPic3D code
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• Implicit time-stepping (“implicit moment method”) • Generalized Minimal Residual (GMRes) solver for the coupled
equations of motion – Maxwell system • Divergence cleaning (Conjugate Gradient) – charge density
continuation assurance
Applications • Reconnection on the Sun; magnetosphere; anywhere • Experiments in plasma devices • Ionization of spacecrafts • PIC – hybrid and PIC – fluid coupling • Mass loss in “hot jupiters”?
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http://www.swiff.eu
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http://www.swiff.eu/
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Annex 1. Timeline of the SWIFF project
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Coupling Solar Simulations with Space Weather: Code Comparison in SWIFF ConsortiumIntroductionMulti-physics in space weatherMulti-scale in space weatherParticipantsSlide Number 6Numerical CodesBenchmarksFlux Rope Emergence SetupSetup ParametersResults: FlipMHDFlipMHD vs MPI-AMRVACDensity Variation in XZ PlaneResults: rise of the ropeConclusionsFuture? Particle-in-cell (PIC)Equations of implicit moment PICiPic3D codehttp://www.swiff.euAnnex 1. Timeline of the SWIFF project