1University of California, San Diego, U.S.A., 2NASA - Goddard Space Flight Center, U.S.A., 3George Mason University, U.S.A., 4Naval Research Laboratory, U.S.A.,

5University of Alabama, Huntsville, U.S.A., 6Nagoya University, Japan

Hsiu-Shan YuHsiu-Shan Yu11, Bernard Jackson, Bernard Jackson11, Paul Hick, Paul Hick11, Andrew , Andrew BuffingtonBuffington11, Nolan T. Luckett, Nolan T. Luckett11, Dusan Odstrcil, Dusan Odstrcil2,32,3, C.-C. Wu, C.-C. Wu44, Tae , Tae

K. KimK. Kim55, Nikolai V. Pogorelov, Nikolai V. Pogorelov55, Munetoshi Tokumaru, Munetoshi Tokumaru66

AbstractAbstract

At the University of California, San Diego (UCSD), remote-sensing analyses of the inner heliosphere have been regularly carried out using interplanetary scintillation (IPS) data for almost two decades. These 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 our iterative UCSD kinematic modeling technique. Additionally, the inclusion of available in-situ measurements into our tomographic analysis allows a more accurate forecast of real-time in-situ density and velocity measurements at Earth. When using the IPS velocity analyses, we accurately convect photospheric magnetic fields on the solar surface outward and thus provide values of the field (radial and tangential components) throughout the global volume. The resulting precise time-dependent results extracted at any solar distance are now used as inner boundary values to drive 3D-MHD models in three different modeling efforts (e.g., ENLIL, H3DMHD, and MS-FLUKSS). We explore the differences between the IPS analyses and each of the current 3D-MHD modeling techniques using the IPS-derived boundaries.

1. Interplanetary Scintillation (IPS)1. Interplanetary Scintillation (IPS)

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 Korean Space Weather Center.

STELab Website:STELab Website:http://stesun5.stelab.nagoya-u.ac.jp/index-e.htmlUSCD Real-Time Website: USCD Real-Time Website: http//:ips.ucsd.edu/CCMC Website: CCMC Website: http://iswa.ccmc.gsfc.nasa.gov:8080/IswaSystemWebApp/index.jsp? KSWC: http//www.spaceweather.go.kr/models/ips

Interplanetary Scintillation (IPS) observations have long been used to remotely-sense small-scale (100-200km) 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. This pattern, measured and correlated between different radio sites in Japan allows a determination of the solar wind speed when translated outward along the line-of-sight to the source. By measuring the scintillation strength of the IPS source, we can also determine the solar wind density.

STELab IPS array systems

500 km

(Jackson et al., 2010; 2013.)

2. 2011/09/24 CME Sequence (Geomagnetic Storm on 9/26) 2. 2011/09/24 CME Sequence (Geomagnetic Storm on 9/26) 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.

CME Height-Time Plots CME Height-Time Plots (C2, C3, HI-1A, WIND)(C2, C3, HI-1A, WIND)

ST23-D2-PM2-P-010ST23-D2-PM2-P-010

Global Solar Wind Boundaries for Use in 3D-MHD Modeling from 3D Reconstruction

of the IPS Remote-Sensing Data

3. Global Solar Wind Boundary3. Global Solar Wind BoundaryEvaluating the 3D reconstruction at a given spherical radius provides a “global solar wind lower boundary” 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 which can then be extrapolated outward by 3D-MHD models. Results of this extrapolation can be compared with with in-situin-situ measurements as a “ground truth” verification of this technique. These inner boundaries are measurements as a “ground truth” verification of this technique. These inner boundaries are extracted at extracted at Earth-centered Heliographic Coordinates at 40 Rs for H3D-MHD MHD modelingEarth-centered Heliographic Coordinates at 40 Rs for H3D-MHD MHD modeling (Wu et al., 2007) (Wu et al., 2007) and at 0.1 AU for ENLIL (Odstrcil et al., 2008), and extracted at Inertial Heliographic Coordinate at 0.25 AU and at 0.1 AU for ENLIL (Odstrcil et al., 2008), and extracted at Inertial Heliographic Coordinate at 0.25 AU for MS-FLUKSS (Kim et al., 2012, 2014).for MS-FLUKSS (Kim et al., 2012, 2014).

ReferencesJackson, B.V., Hick, P.P., Bisi, M.M., Clover, J.M., Buffington, A., 2010, “Inclusion of In-Situ Velocity Measurements into the UCSD Time-Dependent Tomography to Constrain and Better-Forecast Remote-Sensing Observations”, Solar Phys., 265, 245-256.Jackson, B.V., Hick, P.P., Bisi, M.M., Clover, J.M., Buffington, A., 2013, “Inclusion of Real-Time in-situ Measurements into the UCSD Time-Dependent Tomography and Its Use as a Forecast Algorithm”, Solar Phys., 285, 151-165, doi: 10.1007/s11207-012-0102-x).Kim, T.K., Pogorelov, N.V., Borovikov, S.N., Clover, J.M., Jackson, B.V., Yu, H.-S., 2012, “Time-dependent MHD simulations of the solar wind outflow using interplanetary scintillation observations”, AIP Conference 1500, pp. 140-146.Kim, T.K., Pogorelov, N.V., Borovikov, S.N., Jackson, B.V., Yu, H.-S., and Tokumaru, M., 2014, “MHD Heliosphere with Boundary Conditions from a Tomographic Reconstruction Using Interplanetary Scintillation Data”, JGR, (under review).Odstrcil, D., Pizzo, V.J., Arge, C.N., Bissi, M.M., Hick, P.P., Jackson, B.V., Ledvina, S.A., Luhmann, J.G., Linker, J.A., Mikic, Z., Riley, P., 2008. 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.Wu, C.-C., Fry, C.D., Wu, S.T., Dryer, M. and Liou, K., 2007, “Three-dimensional global simulation of interplanetary coronal mass ejection propagation from the Sun to the heliosphere: Solar event of 12 May 1997”, J. Geophys. Res. 112, A09104.

• 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 and ENLIL has been run successfully using these inputs (see poster ST23-D2-PM2-P-013).

4. Summary4. Summary

Comparisons of the 3D-MHD simulation results (ENLIL, H3D-MHD, and MS-FLUKSS) using time-dependent IPS boundaries with the 1-day smoothed WIND data and UCSD kinematic solutions.

Density (a), velocity (b), and radial (c) and tangential (d) magnetic field inner boundaries for H3D-MHD extracted at 40 Rs on 2011/09/24 15 UT from 3D time-dependent tomography using STELab IPS observations and NSO magnetograms.

2011/09/24 CME Sequence: Time-Dependent Boundary for 2011/09/24 CME Sequence: Time-Dependent Boundary for H3D-MHDH3D-MHD

IPS ENLIL H3D IPS ENLIL H3D MSMS

2 2 2 2 2 2

Yellow box enlarged and with 6-hour averaged in situ

0.937

0.877

0.793

0.938

0.522

0.487

IPS

ENLIL

H3D

IPS

ENLIL

H3D

0.7740.565

MSMS

event time event time