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Toward Forecasting Space Weather. Tamas Gombosi The University of Michigan Isradynamics 2010 Conference Ein Bokek (Dead Sea), Israel April 11-16, 2010. Space Weather. - PowerPoint PPT Presentation
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Toward Forecasting Space Weather
Tamas GombosiThe University of Michigan
Isradynamics 2010 ConferenceEin Bokek (Dead Sea), Israel
April 11-16, 2010
Space Weather
Space weather: conditions in geospace that can have adverse effects on space-borne and ground-based technological systems and can endanger human life or health.
(courtesy of Doug Biesecker, NOAA SWPC)
Modeling the Space Weather System
Disparate time scalesDisparate spatial scales
Disparate physics……
☞ Model coupling is needed
Coupled Space Weather Models
Space Weather Modeling Framework (SWMF)Centered at the University of MichiganEnables flexible Sun-to-Earth model chainSingle executable
Center for Integrated Space Weather Modeling (CISM) coupled model
Centered at Boston UniversityEnables Sun-to-Earth model chainMultiple executables
Integrated Magnetosphere-Ionosphere ModelCentered at the University of New HampshireCouples a global magnetosphere, an ionosphere-thermosphere, a radiation belt and a ring current modelSingle executable
Freely available at http://csem.engin.umich.edu
SWMF Capabilities: Physics
Fluid EquationsCompressible HDIdeal MHDSemi-relativistic MHDResistive MHDSingle-fluid Hall MHDTwo-fluid Hall MHDMulti-species (Hall) MHDMulti-fluid (Hall) MHDAnisotropic pressureHeat conduction
Additional PhysicsMultiple materialsNon-ideal EOSRadiation
Gray diffusionMultigroup diffusion
Source termsGravity, mass loading, chemistry, photo-ionization, recombination, etc…
Various resistivity modelsSemi-empirical coronal heatingAlfven wave energy transport and dissipationSelf-consistent turbulence
SWMF Capabilities: Numerics
Time integration SchemesLocal time-stepping for steady stateExplicit (with Boris correction)Explicit/implicitSemi-implicitPoint-implicit
GridsBlock-adaptive treeCartesianGeneralized grids including spherical, cylindrical, toroidal
TVD SolversRoeHLLDHLLEArtificial-windRusanov
LimitersKoren (3rd order)MCBeta
Div(B) control8-waveHyperbolic/parabolic schemeProjectionStaggered grid (CT)
Ray tracingFast & parallel
Synthetic imagesWhite light coronagraphEUV LOS
171Å, 195Å, 284Å
X-ray radiographsTomography
SWMF Capabilities: Framework
Source code:250,000 lines of Fortran in the currently used models34,000 lines of Fortran 90 in the core of the SWMF13,000 lines of Fortran 90 in the wrappers and couplers
User manual with example runs and full documentation of input parametersFully automated nightly testing on 9 different machine/compiler combinationsSWMF runs on any Unix/Linux based system with a Fortran 90 compiler, MPI library, and Perl interpreter
Simulation and Tomography
2005 05 14 21:03 2005 05 15 21:05 2005 05 16 21:00 2005 05 17 21:05
2005 05 18 21:00 2005 05 19 21:05 2005 05 20 21:00 2005 05 21 0306
2005 05 21 21:05 2005 05 22 21:05 2005 05 23 21:00 2005 05 24 21:05
2005 05 25 21:00 2005 05 26 21:05 2005 05 27 21:00 2005 05 27 23:44
ne=106
ne=5x105
Frazin et al., 2008
Thermodynamic Solar Wind Model(van der Holst, Oran and Sokolov)
Sub-photosphere modelMultigroup radiation transportMHDMagnetic flux emergence
Low corona (1R☉r<2.5 R☉)γ=5/3, single temperatureHeat conductionTransport and dissipation of total energy of Alfvénic turbulence (E±)
Wave dissipation represents sources for the plasma momentum and internal energyAdditional coronal heating is obtained from the “unsigned flux” model (Abbett 2007) and observed X-ray luminosity (Pevtsov 2003)
Corona (2.5R☉<r<20R☉)γ=5/3, separate ion and electron temperaturesTransport and dissipation of frequency resolved Alfvén wave intensity, I±(ω)
Kolmogorov spectrum is assumed at the inner boundary
Observational inputs:Magnetogram driven potential field extrapolation (synoptic maps from GONG or MDI)Density and temperatures near the sun are predicted by the DEMT (Differential Emission Measure Tomography) results of Vasquez and Frazin (2009).Solar X-ray luminosity (EIT, STEREO)
Boundary Conditions for CR2077with no Free ParametersGONG magnetogram WSA relation
STEREO/EUVI Differential Emission Measure Tomography (Vasques & Frazin)
CR2077: Two State Solar Wind
In the fast windElectrons are cold (due to adiabatic cooling)Ions are hot (due to Alfvén wave heating)
In the slow windElectrons are hot (due to heat conduction)Ions are cold (no Alfvén wave heating)
Radial velocity
Ion temperature Electron temperature
New Low Corona Model EIT 171Å EIT 195Å EIT 284Å SXT AlMg
Old SC modelsynthesis
New LC modelsynthesis
Observation:Aug 27, 1997
CR1913
Downs et al., ApJ, 712, 1219, 2010
Halloween Storm Simulation: Early Phase
Alfvénic Turbulence and SEP Acceleration
Recent Hinode observations imply that MHD turbulence might be the source that powers, accelerates and heats the solar windToday it is possible to use many dimensional models (>3D)We developed a coupled solar wind-turbulence-SEP model
Separate transport equation is solved for turbulenceWave stress tensor and energy appear in the solar wind momentum and energy equationsEnergetic particles are accelerated by interaction with turbulence
t=7m t=80m t=137m
Sokolov et al., 2009
FTE Simulation (Kuznetsova)
Resolution at the dayside magnetoapuse is 1/16 RE (400 km)Total number of cells in the simulation is 20 millionSolar wind parameters:
n = 2 cm–3
T = 20,000 K Vx = 300 km/sB = 5 nTIMF Turning From Northward (θ = 0∘) to IMF clock angle θ < 120∘
Theta = 120o
Pressure
Subsolar FTE Structure
Cluster
View from South
Component Reconnection Near Sub-Solar Region (Y ~ 0 – 2 RE)And Anti-Parallel Reconnection at Flanks (Y ~ 12 - 15 RE)
View from the Sun
Z-slice
Y-slice
X-slice
FTE at flanks (Y = 12 Re) is connected to FTE at the subsolar region ( Y = 0 ).