Sign in to confirm you’re not a bot
This helps protect our community. Learn more

What do numerical simulations tell us about the magnetic fields of stars?

Institut d'Astrophysique de Paris
29.5K subscribers
299 views 4 years ago
IAP weekly specialised seminars / Friday 6 November 2020: Laurène Jouve, Lab. Astroph., Obs. Midi-Pyrénées (Toulouse, France) In this talk, we will review some aspects of the stellar magnetism and in particular what numerical simulations tell us about the physical processes underlying the observations. In cool Sun-like stars, a convective dynamo is thought to be responsible for the presence and evolution of magnetic fields. One important aspect of stellar dynamos is the possible presence of magnetic cycles, whose caracteristics depend on the stellar parameters. Another question is how magnetic flux is transported from the interior to the surface to produce starspots and whether those spots play a role in the dynamo process. In hotter and more massive stars, the manifestations of a magnetic field are drastically different. Only 5 to 10% of those stars seem to exhibit a strong dipolar magnetic field while most of the other stars are thought to p …...more
...more
These chapters are auto-generated

Intro

0:00

The Sun: a magnetic star

2:05

Magnetic fields in cool stars

6:05

Observations of magnetic cycles on other stars Indirect measurements: chromospheric activity

10:25

Solar interior and plasma flows The Solar Interior

13:38

Theory: the induction equation (MHD)

16:22

Kinematic dynamo ingredients Basic solar dynamo ingredients (kinematic dynamo)

20:10

Magnetic cycles in 2D models

21:05

Magnetic topology in cool stars: influence of the Rossby number

30:34

Ap/Bp stars magnetism

35:06

Theoretical argument

38:25

3D simulations to test theoretical scenario

39:33

Evidence for a magnetorotational instability

40:22

What distinguishes stable from unstable cases?

43:44
What do numerical simulations tell us about the magnetic fields of stars?
N/ALikes
299Views
2020Nov 6
IAP weekly specialised seminars / Friday 6 November 2020: Laurène Jouve, Lab. Astroph., Obs. Midi-Pyrénées (Toulouse, France) In this talk, we will review some aspects of the stellar magnetism and in particular what numerical simulations tell us about the physical processes underlying the observations. In cool Sun-like stars, a convective dynamo is thought to be responsible for the presence and evolution of magnetic fields. One important aspect of stellar dynamos is the possible presence of magnetic cycles, whose caracteristics depend on the stellar parameters. Another question is how magnetic flux is transported from the interior to the surface to produce starspots and whether those spots play a role in the dynamo process. In hotter and more massive stars, the manifestations of a magnetic field are drastically different. Only 5 to 10% of those stars seem to exhibit a strong dipolar magnetic field while most of the other stars are thought to possess a weak complex field. The reason for the existence of this magnetic dichotomy could be linked to the development of magnetic instabilities. We will show in this talk that numerical simulations may help us tackle several of the above key questions about stellar magnetism. Slides available in PDF here: http://www.iap.fr/vie_scientifique/se...

Follow along using the transcript.

Institut d'Astrophysique de Paris

29.5K subscribers