Modelling the effect of Meridional Flows in Time-Distance Helioseismology: Born vs. Ray approximation
Vincent Böning (Kiepenheuer-Institut für Sonnenphysik), Markus Roth (Kiepenheuer-Institut für Sonnephysik, Freiburg, Germany), Jason Jackiewicz (Department of Astronomy, New Mexico State University, Las Cruces, NM, USA), Shukur Kholikov (National Solar Observatory, Tucson, AZ, USA)

Accurate meridional flow measurements are important for understanding the solar dynamo. Recent inversions for meridional flows have not yet reached a consensus on the nature of the meridional flow in depths greater than about 0.9 solar radii. In time-distance helioseismology, current modelling of the solar interior for meridional flow inversions is performed using ray kernels, which assume that waves propagate along infinitely thin ray paths. The Born approximation may constitute a more accurate approach as it models the first order perturbation to the wave field in the whole solar interior. We present the current status of an undergoing validation of a recently developed model for computing spherical Born approximation sensitivity functions suitable for inferring meridional flows. In addition, we compare Born and ray approximations using flow models.