- Conference date: 19–23 March 2012
- Location: Palm Springs, CA, USA
Multipoint SEP (Solar Energetic Particle) event measurements continue to suggest that even modest flarerelated impulsive energetic particle events can have greater-than-expected longitudinal extents. This raises questions concerning the flare source nature and size as well as the possible roles of transport mechanisms including perpendicular diffusion. However it is well-established that open coronal magnetic fields can exhibit large divergence between points near the solar surface and the radius where solar wind dominates, and that this can spread SEP fluxes from a small source over a broad heliospheric volume. Potential Field Source Surface (PFSS) models are often used to determine whether open coronal field lines connecting the observer to a flaring active region can explain widely separated impulsive SEP event observations. But while such 'mappings' of suspected sources to the observation sites can succeed, as many others seem to fail. The reasons may be physical but they may also be related to the model applications. We examine some potential sources of error related to the users' choices of assumptions and parameters in the PFSS model field mappings including the size and location of the flare source footprint at the Sun, the order of the spherical harmonic reconstruction of the coronal field, and the chosen radius of the model source surface. An example from August 2010 is used to illustrate the sensitivity of the results to these choices, providing insights and cautionary notes for model users.
- Solar corona
- Magnetic fields
- Solar energetic particles
- Solar magnetic fields
Data & Media loading...
Article metrics loading...