HR: 1340h
AN: SH14A-1689    [Abstracts]
TI: A Forecast of the Termination-Shock Position
AU: * Washimi, H
EM: washimih@ucr.edu
AF: IGPP, University of California at Riverside, 900 University Ave, Riverside, CA 92521, United States
AU: Zank, G P
EM: gary.zank@ucr.edu
AF: IGPP, University of California at Riverside, 900 University Ave, Riverside, CA 92521, United States
AU: Hu, Q
EM: qiang.hu@ucr.edu
AF: IGPP, University of California at Riverside, 900 University Ave, Riverside, CA 92521, United States
AU: Tanaka, T
EM: tatanaka@geo.kyushu-u.ac.jp
AF: Faculty of Science, Kyushu University, Hakozaki, Fukuoka, 812-8581, Japan
AU: Munakata, K
EM: kmuna00@gipac.shinshu-u.ac.jp
AF: Faculty of Science, Shinshu University, Matsumoto, Matsumoto, 390-8621, Japan
AB: The effects of heliospheric disturbances on the position of the termination shock (TS) are examined using a three-dimensional MHD model. Variations in the solar wind ram-pressure due to the interplanetary shock waves drive the TS from its steady-state equilibrium position, and emit shocks and waves downstream. Transmitted/emitted disturbances propagating from the TS to the heliopause (HP) are partially reflected at the HP, and the reflected waves return and collide with the TS. Thus, besides upstream solar wind disturbances, the TS position changes in response to incident downstream disturbances associated with waves reflected from the heliopause produced by earlier supersonic solar wind disturbances. To determine the time-varying TS position, we incorporate Voyager 2 (V2) plasma data as a boundary condition into our 3D MHD simulations, which allows us to forecast the termination shock movement for nearly a year after the present V2 data. Our simulations indicate that the TS was at about 92AU along the sun-V1 line on August 14, 2007, the last tentative available date of the V2 data. After this, our simulation forecasts that the TS position will continue to decrease to a minimum distance in late 2007 or early 2008. This decrease will be caused by the heliosheath returned-pulse driven by the March 2006 event. Whether V2 will cross the TS or not in this period depends on the future SW ram-pressure and also on the degree of the north-south asymmetry of the heliospheric structure. Some quantitative discussions are given.
DE: 2100 INTERPLANETARY PHYSICS
DE: 2124 Heliopause and solar wind termination
DE: 2126 Heliosphere/interstellar medium interactions
DE: 2164 Solar wind plasma
DE: 2447 Modeling and forecasting
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2007 Fall Meeting