Paul Cally

Stay at the IAC: 30/04/2015 to 28/06/2015 
Research line: Solar Physics

Prof. Prof. Paul S. Cally will give a Severo Ochoa-Jesús Serra Foundation seminar at the IAC.

Dr. Cally is currently full Professor of Solar Physics in the School of Mathematical Sciences at Monash University (Melbourne, Australia), position he has held since 2003.

He obtained his PhD in Applied Mathematics from Monash in 1980, and held postdoctoral positions in the UK before returning to Monash as a lecturer in 1984. He has been an Affiliate Scientist at the High Altitude Observatory of the National Center for Atmospheric Research in Boulder, Colorado, USA since 1998.

Prof Cally's research mainly concerns waves and instabilities in the solar plasma. He is a foremost expert on magnetohydrodynamics mode conversion and applications to solar activity. Dr. Cally has made fundamental contributions to magnetohydrodynamic (MHD) wave and instability theory, with particular reference to the Sun: definitive theory of leaky tube waves; new interpretation of MHD phase mixing as a cascade in wavenumber space; solution of the sunspot p-mode absorption problem in terms of fast-to-slow mode conversion (both analytic and the first numerical simulations confirming the process); identification of several new instabilities in toroidal tachocline magnetic field; development of a generalized ray theory that quantitatively models mode conversion; identification of fast-to-Alfvén mode conversion as an important process in wave behaviour in active región atmospheres, and to local seismology (travel times).

Modelling some of the above mentioned processes in collaboration with E. Khomenko and her group (M. Collados, N. Vitas, M. Luna, A. De Vicente, P. González e I. Calvo) will be the focus of his visit to the IAC. Applications are foreseen in one (or several) of the following topics: extension of fast-Alfvén conversión theory to complex and realistic magnetic geometries; multiple scattering from ensembles of flux tubes; time-distance seismology of sunspots; implications for helioseismic inversion and acoustic halos; detailed modelling of spectral signatures of MHD atmospheric oscillations.