1. The “cone model” was originally developed by Zhao et al. ~10 (?) years ago in order to interpret the times of arrival of ICME ejecta following SOHO LASCO observations of halo CMEs- which were known to produce geoeffects more often than other CMEs. This poster provides an update on the approach that CISM is taking to develop a simplified model of a CME’s effects on the solar wind, namely the transient disturbances known as ICMEs that are the major cause of large geomagnetic storms. Case studies with the cone model include the halo CME in May 1997 that is also being simulated by CISM in a more detailed way starting at the Sun (see accompanying poster on the initiation of this event in the coronal model). Other potential case studies are described here, including cases involving multiple CME disturbances that interact in ways that modify their individual effects. Overall the cone model allows us to proceed in developing the heliospheric portions of the model, to explore the effects of interaction with the solar wind structure, and to develop model products necessary for SEP event simulations and geospace coupling. CISM Cone Model Approach to Interplanetary CME (ICME) Simulation D. Odstrcil 3,4, X-P. Zhao 5, Y. Liu 5, T.J. Hoeksema 5, C.N. Arge 6, S. Ledvina 1, P.Riley 2, J. Linker 2 1 University of California, Berkeley, 2 SAIC, 3 University of Colorado, 4 NOAA-SEC, 5 Stanford, 6 AFRL May 12, 1997 May 1, 1998 The ejecta has no magnetic structure and so best represents an ICME’s leading shock, sheath, and trailing rarefaction region. This may be useful for providing a global context, predicting whether shocks and/or ejecta will hit geospace, and some SEP applications. ICMEs (white shaded structures), IMF lines (colored by normalized density), during the April/May 1998 events. Geospace is magnetically connected to stronger shock front when a rarefaction region, caused by the preceding ICME, is present. ICMEs and IMF Connectivity Simulation of Interplanetary CMEs Coronal Mass Ejections (CMEs) and the Cone Model High Resolution of Shocks at Geospace Multiple Transient Events http://cdaw.gsfc.nasa.gov/CME_list/  5 halo CMEs between April 27 and May 2, 1998  total 18 CMEs between April 27 and May 2, 1998 CME-1 CME-3CME-4CME-5CME-2 CME-3 April 21, 2002 August 24, 2002. Nested grids with progressively finer resolution centered on geospace is used to achieve high resolution of interplanetary shocks hitting the magnetosphere. Global (left) and detail (right) view show an interplanetary transient with the distorted shock front as it propagates through a moderate streamer. Upper and lower half show solution on single and nested grids. L1-point and Earth position is marked by white diamond and rectangle, respectively. CME-1 CME-4 CME-2 CME-3 CME-5 Weak (top left) and strong (top right) energetic particle events were observed by GOES spacecraft. The IMF line traced from the geospace to inner boundary of the heliospheric domain shows proximity of two solar active regions and an interplanetary shock in the latter case. First, background solar wind is computed using the output from either the WSA empirical or MAS numerical coronal model. Then, an over-pressured plasma cloud (with location, diameter, and speed from the cone model) is launched into heliosphere. Resulting interplanetary disturbance has two-part structure (shock+ejecta) and forward-reverse shock pair structure may form by cloud expansion.