Science Seminars

5/14/2015 – Space Weather and the Current Sheet Source Surface (CSSS) Model

Speaker: Bala Poduval (Space Science Institute)
Date: Thursday, May 14, 2020
Time: 4:00 PM
Location: SPSC W120

Seminar Abstract:

An inverse correlation between the observed solar wind and the rate of expansion of magnetic flux tubes (FTE) within photosphere and inner corona was shown to exist by Levine et al. (1977). Wang and Sheeley, through a series of papers in the 1990s, established an empirical relationship between solar wind speed and FTE, suggesting that all the solar wind emanates from coronal holes — the fast wind from the centers and the slow wind from the boundaries. This empirical relationship forms the basis of the state-of-the-art solar wind prediction technique: the Wang-Sheeley-Arge (WSA) model, built on the well-known potential field source surface (PFSS) model.

The Current Sheet Source Surface (CSSS) model (Zhao & Hoeksema 1995), built on a corona in magnetostatic equilibrium incorporating electric currents, depicts realistic coronal scenario. I present results of an investigation of the predictive capabilities of the CSSS model in the context of Space Weather and, thereby, establish the Sun-Earth connections. A comparison is drawn with PFSS model and WSA/ENLIL model. Here, the solar wind is computed using the FTE computed using the respective models. On average, the CSSS predictions were more accurate than the PFSS and WSA/ENLIL predictions by a factor of two, approximately, taking the Root Mean Square (RMS) error as the metric of accuracy. We attribute the greater accuracy of the CSSS predictions to the model’s capability to trace the solar wind sources better than the PFSS model.