Three-Dimensional Tomography of Interplanetary Disturbances

Astrophysics and Space Science Library 314, 355-386, 2005

Chapter 17 in: Solar and Space Weather Radiophysics,
Current Status and Future Developments,
D.E. Gary and C.U. Keller (eds.)
© Kluwer Academic Publ.

Three-Dimensional Tomography of Interplanetary Disturbances

B.V. Jackson and P.P. Hick
Center for Astrophysics and Space Science, University of California, San Diego, CA 92093-0424, USA

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 July 14, 2000 Bastille-day halo CME and other intervals using archival Cambridge IPS data, and Helios photometer Thomson-scattering data. We compare our results with additional remote-sensing observations, and in situ observations from near-Earth spacecraft. When heliospheric remote sensing observations (IPS and/or Thomson-scattering) are available in real time, this CAT technique provides a novel method to predict solar wind conditions at Earth at least one day ahead of time. We run one such forecast project based on IPS data received from the Solar Terrestrial Environment Laboratory, Japan.