Three-Dimensional Tomography of Interplanetary Disturbances

Abstract

We have developed a Computer Assisted Tomography (CAT) program that modifies a three-dimensional kinematic heliospheric model to fit interplanetary scintillation (IPS) or Thomson scattering observations. The tomography program iteratively changes this global model to least-squares fit the data. Both a corotating and time-dependent model can be reconstructed. The short time intervals of the time-dependent modeling (to shorter than 1 day) force the heliospheric reconstructions to depend on outward solar wind motion to give perspective views of each point in space accessible to the observations, allowing reconstruction of interplanetary Coronal Mass Ejections (CMEs) as well as corotating structures. We show these models as velocity or density Carrington maps and remote views. We have studied several events, including the 2000 July 14 Bastille-Day halo CME and several intervals using archival Cambridge IPS data, and we have also used archival Helios photometer data to reproduce the heliosphere. We check our results by comparison with additional remote-sensing observations, and in-situ observations from near-Earth spacecraft. A comparison of these observations and the Earth forecasts possible using them is available in real time on the World Wide Web using IPS data from the Solar Terrestrial Environment Laboratory, Japan.