daily real-time MHD simulation of global solar corona and solar wind

[ official version ] [ test version ] [ Japanese version ] of HMI daily-MHD model.

The global solar corona and solar wind
derived with time-dependent three-dimensional MHD simulation
using SDO/HMI magnetic-field synoptic data

input data and initial PFSS magnetic field	daily NRT simulation	other solar obs.

Details of this simulation is described in Solar Physics (2015) vol.290, 1507.
For information about instruments, data, and the status of data processing, please visit HMI and/or SOI/SOHO/MDI web pages.

Input NRT Synchronic-Frame Map of Solar-Surface Magnetic Field :

synoptic frame map

latest map in FITS format (∼ 20MB)
and WSO data format (∼ 21kB).
year-to-date(*) mp4

PFSS model plot

left : field lines and bases of open field
right: zero-Br contour surfaces.
3-D FITS data: radial, lat., and long..
year-to-date(*) mp4

PFSS (without Br-offset)

left : field lines and bases of open field
right: zero-Br contour surfaces.
3-D FITS data: radial, lat., and long..
year-to-date(*) mp4

* Not regularly updated.
The daily-updated map are found at http://jsoc.stanford.edu/ajax/lookdata.html?ds=hmi.Mrdailysynframe_720s_nrt

Around 14:00 UT (7 or 8AM PT) everyday, a latest daily-updated synoptic map is generated in JSOC data pipeline. At 10 AM PT, the coronal MHD module loads the latest map and start a time-relaxation simulation. Plots of PFSS calculations above are updated usually around 10:30AM PT. A daily MHD real-time low-resolution simulation is completed around 11:30 AM to 12:30PM PT. The elapsed time depends upon primarily the largest absolute eigen values of the hyperbolic equation system, or roughly the largest value of the magnetic field strength (the CFL condition).

Daily NRT Simulation Data

NRT daily simulation data generated through automated JSOC data pipeline are found at http://jsoc.stanford.edu/ajax/lookdata.html?ds=hmi.MHDcorona_daily_nrt.


plots made: 
Sun Mar 9 18:56:26 UTC 2025 (Sun Mar 9 11:56:26 PDT 2025)

lat-lon map at various distances click here to enlarge.	coronal brightness (white corona) and coronal holes	field line and speed (blue-yellow-red : stagnant-slow-fast)

recent 27 plots (mpeg movie) year-to-date(*) mp4	recent 27 plots (mpeg) year-to-date(*) mp4

* Not regularly updated.

Latest data files *Please contact us for details of the simulation and data.

maps at 30 Rs: Vr (in km/s) and Br (in nT) in CSV (Comma Separated Values; plain text) format

a cubic data containing all eight MHD variables : click here (FITS format, approx. 6.5MB).
This single FITS file contains all eight simulated MHD variables, from 1.01 to 4.96 Rs. The size of this cubic data is 32 x 64 x 640. The first 80-layer block, (*,*,0:79), is for the density (in count/cc) at heights of (1.01 + i * 0.05) Rs, i.e., from 1.01 Rs to 4.96 Rs with a fixed equi-radius interval of 0.05Rs. The second to eighth 80-layer blocks are respectively for the temperature (in MK), V_r, V_theta, V_phi (in km/s), B_r, B_theta and B_phi (in Gauss). Please mind that the format and specifications of this FITS file are different from those at JSOC database.

Summary movies:

2025		2024		2023		2022		2021		2020
2nd	1st	2nd	1st	2nd	1st	2nd	1st	2nd	1st	2nd	1st
				lat.long corona	lat.long corona	lat.long corona	lat.long corona	lat.long corona	lat.long corona	lat.long corona	lat.long corona
2019		2018		2017		2016		2015		2014
2nd	1st	2nd	1st	2nd(*)	1st	2nd	1st	2nd	1st	2nd	1st
lat.long corona	lat.long corona	lat.long corona	lat.long corona	lat.long corona	lat.long corona	lat.long corona	lat.long corona	lat.long corona	lat.long corona	lat.long corona	lat.long corona
2013		2012		2011		2010		2009		2008
2nd	1st	2nd	1st	2nd(d)	1st(c)	2nd(b)	1st	2nd	1st	all(a)
lat.long corona	lat.long corona	lat.long corona	lat.long corona	lat.long corona	lat.long corona	lat.long corona	lat.long corona	lat.long corona	lat.long corona	lat.long corona

(*) Many movie frames are missing because of disk failutre.
(d) SDO/HMI daily synoptic maps have been regularly generated at JSOC, and used in this daily-MHD model, from July 1. 2011.
(c) Transition of input data, from MDI to HMI.
(b) SOHO/MDI daily-updated synoptic maps were used until the end of 2010.
(a) Polar-field correction was applied to the input MDI synoptic map data, except for a few earliest weeks.

Simulations with definitive synoptic map data

definitive daily data :	magnetic field map and three-dimensional MHD data
definitive once-a-Carrington-Rotation data :	magnetic field map and three-dimensional MHD data

*) Definitive version of input synoptic or synchronic frame maps of solar-surface magnetic field and MHD output data are generated when all calibrations are applied, usually a month after observations.

Observations / Measurements


external images/data fetched: 
Sun Mar 9 11:30:16 UTC 2025 (Sun Mar 9 04:30:16 PDT 2025)

HMI synchronic frame map

HMI full-disk

HARP

LASCO and AIA

C2 and AIA

MHD corona

AIA

CH(PFSS)

PFSS line and zero-Br surf.

ACE real-time mag.epam

ACE real-time mag.

ACE real-time epam

STEREO Synop.

STEREO A COR2

STEREO A COR1

STEREO A 195

STEREO B 195

STEREO B COR1

STEREO B COR2

Description

polar field correction :
Because of variety of factors, measurement of polar field is generally of low quality. The polar field correction is needed to improve model outputs and enhance our understandings on the solar corona and solar wind. Our correction is based on the spline extrapolation with respect to both time and space, proposed and tested by X. Sun, Y. Liu, J.T. Hoeksema, and X.P. Zhao. See details in our paper.
initial and boundary values of magnetic field :
The boundary and three-dimensional initial value of the magnetic field are then calculated with the potential-field source-surface (PFSS) model. In this daily simulation, the spherical harmonics decomposition up to the 5th order is used to calculate PFSS solution.
MHD simulation :
Time-dependent three-dimensional MHD model is used to simulate time-relaxation process from PFSS-based initial state to steady state of the sub/trans-alfvénic solar corona. The simulation scheme here is based on the Lax-Friedrichs method that is a simplified version of the TVD Roe/Godunov method. The daily quasi-real-time simulation shown above assumes fixed density and temperature at the coronal hole base (labeled choice O in our paper).
The number of grids for daily NRT simulation are 72, 32 and 64 for the radial, latitudinal and longitudinal direction, respectively. The inner boundary of simulation is set at 1.01 solar radii, so that we will handle the coronal plasma already heated up to the order of 1 MK though the solar transition region.
Temporal evolutions of eight MHD variables at this height are controlled by using the normal projected characteristics method, so that the obtained time-relaxed solution can be fully consistent with a given boundary map and satisfy the basic nonlinear hyperbolic MHD equations and the concept of characteristics: at each time step, this boundary treatment redistributes calculated temporal derivatives in accordance with given constraints and mathematical requirements. The radial component of surface magnetic field is fixed all through a simulation. Whether plasma will be flowing outward (at coronal hole) or be stagnant (in closed-field streamer) is determined by nonlinear interaction between plasma and magnetic field.
The polytrope plasma with specific heat ratio of 1.05 is assumed here to mimic near-isothermal situation in the solar corona. This assumption yields somehow small contrast in flow speed and density, and values of plasma (velocity and density) are not indeed realistic. Still the magnetic field quantities and trends of these plasma variables can be well retrieved.
quick links to related sites : CGEM, CISM, SDO / HMI, SOHO / MDI

modification / change / history

2015 Oct. : Latest minor correction/update in text.
2012 Jan. 16 : Start using final version of SDO/HMI daily-updated synoptic map.
2011 July 1 : Start using test version of SDO/HMI daily-updated synoptic map.
2011 Jan. : SOHO/MDI measurement ceased.
2010 May : SDO/HMI started regular observation.
2008 July 1 : Newkirk filter and other tweaks are applied to synthetic coronagraph image.
2008 May 11 : This webpage became publicly-accessible.
2008 Mar. 1 : Polar field correction is introduced for MDI data map.
2008 Feb. 8 : Daily simulation starts.

K. Hayashi

The global solar corona and solar wind derived with time-dependent three-dimensional MHD simulation using SDO/HMI magnetic-field synoptic data

The global solar corona and solar wind
derived with time-dependent three-dimensional MHD simulation
using SDO/HMI magnetic-field synoptic data