Seismic Imaging of the Solar Interior

News

(29.12.2009) Milestone #2: "Modeling the subsurface structure of sunspots" by H. Moradi et al. submitted to the journal Solar Physics.

Abstract: While sunspots are easily observed at the solar surface, determining their subsurface structure is not trivial. There are two main hypotheses for the subsurface structure of sunspots: the monolithic model and the cluster model. Local helioseismology is the only means by which we can investigate subphotospheric structure. However, as current linear inversion techniques do not yet allow helioseismology to probe the internal structure with sufficient confidence to distinguish between the monolith and cluster models, the development of physically realistic sunspot models are a priority for helioseismologists. This is because they are not only important indicators of the variety of physical effects that may influence helioseismic inferences in active regions, but they also enable detailed assessments of the validity of helioseismic interpretations through numerical forward modeling. In this paper, we provide a critical review of the existing sunspot models and an overview of numerical methods employed to model wave propagation through model sunspots. We then carry out an helioseismic analysis of the sunspot in Active Region 9787 and address the serious inconsistencies uncovered by Gizon et al. (2009). We find that this sunspot is most probably associated with a shallow, positive wave-speed perturbation (unlike the traditional two-layer model) and that travel-time measurements are consistent with a horizontal outflow in the surrounding moat.

(01.06.2009) Milestone #1. Compute cluster operational (real-time monitoring).

(01.09.2009) Dr. Raymond Burston joins SISI to work on travel-time sensitivity kernels.

(01.03.2009) Dr. Hamed Moradi joins SISI to work on parametric sunspot models.

(07.10.2008) Conference "Le Conseil européen pour la recherche pour une politique d'excellence: les premiers jeunes lauréats ouvrent la voie", Collège de France, Paris. [Read SISI project summary]

(01.08.2008) SISI project officially starts.

(11.07.2008) Grant agreement signed.

(05.06.2008) Postdoctoral Fellowships: Positions have been filled!

(13.02.2008) Prime Minister Francois Fillon receives ERC StG finalists.

(05.02.2008) Minister of Higher Education Valerie Pecresse congratulates ERC StG finalists.

(24.01.2007) ERC publishes the results of the first ERC Starting Grant competition. Project "Seismic Imaging of the Solar Interior using space-based data" ranked 243 out of over 9000 applications.