1. 2014SWW - S9
3D Reconstruction of IPS Remote-sensing Data: Global Solar Wind Boundaries for Driving 3D-MHD Models
Hsiu-Shan Yu1, B.V. Jackson1, P.P. Hick1, A. Buffington1,
D. Odstrcil2, Chin-Chun Wu3, and M. Tokumaru4
1Center for Astrophysics and Space Sciences, University of California, San Diego
9500 Gilman Drive #0424, La Jolla, CA , U.S.A;
2George Mason University, VA and NASA/GSFC, USA
3Naval Research Laboratory, Washington, DC, U.S.A.
4STE Lab, Nagoya University, Furo-cho, Chikusa-ku, Nagoya , Japan
(Sponsored by: AFOSR FA , NSF AGS , and the KSWC, Jeju, South Korea)
Abstract
The University of California, San Diego (UCSD) interplanetary scintillation (IPS) tomographic remote-sensing analyses of the heliosphere have reconstructed 3D solar wind velocities and densities for nearly two decades. These global results, especially using Solar-Terrestrial Environment Laboratory (STELab) IPS observations, enable a real-time forecast of solar wind density and velocity that is nearly complete over the whole heliosphere with a time cadence of about one day, using the iterative UCSD kinematic modeling technique. Additionally, inclusion of available in-situ measurements into the analysis provides a more accurate forecast of real-time in-situ density and velocity observations at Earth. The IPS volumetric velocity from this time-dependent tomography accurately convects photospheric magnetic fields from near the solar surface outward using a modified potential field model, and thus provides field values (both radial and tangential components) throughout the global volume. Moreover, precise results extracted at any solar distance are now used as inner boundary values to drive 3D-MHD models (e.g., ENLIL, and H3DMHD) allow us to explore the differences between the IPS analyses and each of the current 3D-MHD modeling techniques. These differences provide interesting insights into the physical principles governing the expulsion of CME mass.
1. Interplanetary Scintillation (IPS)
STELab IPS array systems
500 km
Interplanetary Scintillation (IPS) observations have long been used to remotely-sense small-scale ( km) heliospheric density variations along the line of sight in the solar wind. These density inhomogeneities in the solar wind disturb the signal from point radio sources to produce an intensity variation when projected on the ground, whose pattern travels away from the Sun with the solar wind speed.
Solar-Terrestrial Environment Laboratory (STELab) radio array, Japan; the Fuji system is shown. USCD currently maintains a near-real-time website that analyzes and displays IPS data from the STELab. This modeling-analysis capability is also available at the CCMC (Community Coordinated Modeling Center) and the KSWC (Korean Space Weather Center) Jeju, South Korea.
This pattern, measured and correlated between different radio sites in Japan allows a determination of the solar wind speed. By cross-correlating the radio signal obtained at different IPS observing sites, we determine the solar wind speed. By measuring the scintillation strength of the IPS source, we can also determine the solar wind density.
STELab Website:
USCD Real-Time Website: http//:ips.ucsd.edu/ CCMC Website:
KSWC Website:
(Jackson et al., 2010; 2012.)
/09/24 CME Sequence (Geomagnetic Storm on 9/26)
CME-1
COR2
STEREO-A
CME-2
CME-2
CME-1
A pair of closely-spaced CMEs erupted from NOAA AR1302 on September 24th 2011 in conjunction with an M7 strength solar flare, on 1237 UT September 26th. The ACE and WIND spacecraft detected a solar wind increase from 350km/s to over 700 km/s at its peak. Bz became sharply south at times (-30nT) and a strong G3 to G4 Level Geomagnetic Storm occurred at high latitudes.

2. 2b. CME Height-Time Plots (C2, C3, HI-1A, WIND)
3. Global Solar Wind Boundary (ftp://cass185.ucsd.edu/data/IPSBD_Real_Time/)
Evaluating the 3D reconstruction at a given spherical radius provides a “global solar wind lower boundary” which can then be extrapolated outward by 3D-MHD models. Results of this extrapolation can be compared with in-situ measurements as a “ground truth” verification of this technique. These inner boundaries are extracted at Earth-centered Heliographic Coordinates at 0.1 AU for ENLIL 3D-MHD modeling (Odstrcil et al., 2008) and at 40 Rs for H3D-MHD (Wu et al., 2001).
Density (a), velocity (b), and radial (c) and tangential (d) magnetic field inner boundaries for ENLIL extracted at 0.1AU from 3D time-dependent tomography using STELab IPS observations and NSO magnetograms.
Comparisons of the 3D-MHD simulation results (ENLIL and H3D-MHD) using time-dependent IPS boundaries with the WIND data and UCSD kinematic solutions.
IPS
IPS
0.938
0.937
ENLIL
ENLIL
0.515
0.847
H3D
H3D
0.487
0.793
IPS
ENLIL
H3D
IPS
ENLIL
H3D
3-hour averaged in situ
4. Summary
The analysis of IPS data provides low-resolution global measurements of density and velocity with a time cadence of one day for both density and velocity, and slightly longer cadences for some magnetic field components.
The 3D-MHD simulation results using IPS boundaries as input compare fairly well with in situ measurements. Real-time IPS boundary data for driving MHD model (ENLIL) are now available.
References
Jackson, B.V., Hick, P.P., Bisi, M.M., Clover, J.M., and Buffington, A., 2012, “Inclusion of Real-Time in-situ Measurements into the UCSD Time-Dependent Tomography and
Its Use as a Forecast Algorithm”, Solar Phys., (published on line ) doi: /s x).
Jackson, B. V., P.P. Hick, M.M. Bisi, J.M. Clover, A. Buffington, 2010, “Inclusion of In-Situ Velocity Measurements into the UCSD Time-Dependent Tomography to Constrain
and Better-Forecast Remote-Sensing Observations”, Solar Phys., 265,
Wu, S. T., H. Zheng, S. Wang, B.J. Thompson, S.P. Plunkett, X.P. Zhao, M. Dryer, 2001, “Three-dimensional numerical simulation of MHD waves observed by the Extreme
Ultraviolet Imaging Telescope”, J. Geophys. Res. 106,
Odstrcil, D., et al in ASP Conference Series Proceedings - Numerical Modeling of Space Plasma Flows, eds. N. V. Pogorelov, E. Audit, & G. P. Zank , “Numerical
Simulations of Solar Wind Disturbances by Coupled Models”, 385, 167.