Geoph•,Mcal In.sl/lule. Un/vc/'•s/lv o/ ,qlas/,a An Euler-Laorange coordinate transtbrmation •.s applied to a compt•ted solar wind velocity data ,,et lo obtain fluid streamlines which are also magnetic field lines. Plolting these lines high-resolul•on simulation data provides delailed intbrmal•on aboul the time variation of torotatung interaction regions in the equalorial plane of the hellosphere. 13,692 Olmsted and Akasofu: Brief Reporl O!msted anti Akasofu' Brief Reporl 13,693 /tcl, nowledgmems The work reporled herc was supported •n particle stream flow willa application to solar wind par! by a gran! from the National Aeronautics and Space simulation, Planet. Space Sci. 33, 831, 1985. Administration (NSG 7447) and the National Science Foundation Pizzo, V. J., A three-dfmensional model of corotating streams in (ATM 85-114512). The Editor thanks R. S Steinolt•son and B T Thomas their assistance in evaluating this paper. REFERENCES &kasot•, ,q ! • Fill•us. W Sun, C. Fry, and M. Dryer. ,• ,,•l•l;.il•O• xlt•tJ\ ot lwo nla.jor events in the heliosi•hcrc dtlt•ne the presen! •t•nspot cycle, J Geop?.s. Res., 90, 8193, the solar wind, 1, Theoretical tbundation, J Geohv.s Re•s. 83. 5563, 1978. P•z>,o, V J., A three-dimensional model of cotorating streams the solar wind, 2, Hydrod)namic •treams. J Geophvx Re.s, Pi//o, V J., A three-dimensional model of cotorating streams the solar •i•ti, 3, Magnetoh)cirodvnamic streams, J Res 87, 4374, 1982. Smith. Z. k. M. Dryer and R. S. Steinolfson, A slt•clx oJ' the tbrmation. c•olulion and ctecax of shocks •} lhc heliosphone between 0.5 and 30.0 AU, J. Gcoi)hvs Res. 90. 217, 1985.AitVen H The .sun'.,, ecneral magnetic field, 7k, lht.s. 8. 1, 1956 Sleinolf.,,on, R. S., M. Dryer and 5. Nakagawa, Numerical Burlaga L F. F B.•McDonalci, N. F. Ness, R. Schwenn, A MHD •imulation of interplanetarx shock pairs, J. Geophvs J La/a•u•. and F Mariani, Interplanetar• tlo• •xslcms Re• 80. 1223, 1975. associated with cosmic rav modulation in 1977-19•0, J •Vhano 5' C. A magnelohvdrodvnamic model tbr corotating Ge(,!)ln's R•,s 80, h579, 198•.