Asymptotics in Astrophysics SG Seminar
2 events
-
Seminar
Asymptotic Waves in Stars
April 23 (Wed) at 14:00 - 15:30, 2025
Jim Fuller (Professor, Division of Physics, Mathematics, and Astronomy (TAPIR), California Institute of Technology (Caltech), USA)
Waves propagating through stars often have very short wavelengths in the radial direction, enabling WKB approximations that facilitate understanding. The main types of waves that propagate in stars are acoustic waves (restored by pressure forces) and gravity waves (restored by buoyancy forces). I will also discuss how the properties of these waves are changed by rotation (adding Coriolis and centrifugal forces) and magnetic fields (adding Lorentz forces). Finally, I will discuss how these waves carry energy and angular momentum through stars, and discuss some potential consequences for stellar evolution.
Venue: Hybrid Format (3F #359 and Zoom), Seminar Room #359
Event Official Language: English
-
Seminar
asymptotics in astrophysics SG session 4: helioseismology
November 29 (Fri) at 10:30 - 12:00, 2024
Ryota Shimada (Ph.D. Student, Department of Astronomy, Graduate School of Science, Kyoto University)
Constraining the distribution of internal magnetic fields through observations is considered to advance solar dynamo models aimed at understanding the 11-year cycle of solar magnetic activity. This paper [1] is on the frequency shift of standing acoustic waves inside the Sun caused by internal magnetic fields. Quasi-degenerate perturbation theory is applied to treat perturbation by magnetic fields. I’d like to discuss their methods and application in the session.
Venue: Seminar Room #359 / via Zoom
Event Official Language: English
2 events