Workshop : Asymmetric instabilities in stellar core collapse
June 30 - July 11, 2008 - Institut Henri Poincaré, Paris

Asymmetric instabilities

in stellar core collapse

June 30 – July 11, 2008

Institut Henri Poincaré, Paris 

Organizing committee:
(CEA-Saclay, organizer)
H.Th. Janka (MPA Garching, co-organizer)


Scientific overview:

The physical mechanisms responsible for the explosion of massive stars are still not well understood. The discovery of new hydrodynamic instabilities, like the SASI and large amplitude neutron star g-modes in the context of stellar core collapse, has enabled a significant progress of our theoretical understanding of the processes that play a role in the cores of collapsing massive stars, and the conditions for the birth of neutron stars.

Over the past years, numerical simulations have revealed that these instabilities can be a key ingredient for successful supernova explosions: either in the classical scenario driven by neutrino energy deposition, or through a new acoustic mechanism involving the acoustic energy flux produced by g-mode oscillations of the nascent neutron star. 
These asymmetrical instabilities are also capable of providing neutron star kicks, may influence their spin, and can lead to gravitational wave emission and special features of the neutrino emission.

While the complexity of the numerical models increases towards a 3D dynamical description of the rotating, magnetized collapsing core, the fundamental properties of these instabilities are still being debated and deserve clarification.

This workshop aims at discussing these recent advances by allowing productive interactions between experts using different numerical techniques and analytical methods.

In particular the following topics will be discussed during the meeting:

  • Possible explosion mechanisms for supernovae
  • Rotation of the progenitor and magnetic field: from classical SN to hypernovae and GRBs
  • Signatures of the explosion mechanism in :
the kick and spin of the pulsar
neutrino emission
gravitational waves
  • Underlying mechanism of SASI: acoustic or advective-acoustic ?
  • Comparing SASI with other shock instabilities
  • Towards a MHD version of SASI
  • Spiral mode of SASI in 3D simulations

List of invited participants

E. Audit (CEA Saclay) B. Müller (MPA Garching)
C. Cardall (Oak Ridge Nat. Lab. & UT Knoxville) H. Mikami (Chiba Univ.)
L. Dessart (Steward Obs. & Princeton Univ.) J. Murphy (Univ. Washington, Seattle)
T. Foglizzo (CEA Saclay) M. Obergaulinger (MPA Garching)
J. Guilet (CEA Saclay) N. Ohnishi (Tohoku Univ.)
T. Hanawa (Chiba Univ.) C. Ott (Univ. Arizona, Tucson)
W. Iwakami (Tohoku Univ.) J. Sato (CEA Saclay)
H.Th. Janka (MPA Garching) S. Scheidegger (Univ. Basel)
R. Käppeli (Univ. Basel) Y. Suwa (Tokyo Univ.)
K. Kotake (NAOJ, Tokyo) T. Takiwaki (Tokyo Univ.)
J.M. Laming (NRL, Washington) J.C. Wheeler (Univ. Texas, Austin)
M. Liebendörfer (Univ. Basel) S. Whitehouse (Univ. Basel)
E. Livne (Univ. Jerusalem) S. Yamada (Waseda Univ.)
A. Marek (MPA Garching) T. Yamasaki (CEA Saclay)
J. Margueron (IPN Orsay)

Programme, slides and video download

 The talks can be downloaded by clicking on the corresponding icons: 

  for pdf slides, and  for mp4 video


Monday, June 30

9:30   LOC   Welcome at IHP & Registration        
10:30       coffee        
14:30   J. Murphy   Criteria for core-collapse supernova explosions by the neutrino mechanism    
15:30       tea        

 Tuesday, July 1

9:30   J.M. Laming   Analytic approach to the stability of standing accretion shocks    
10:30       coffee        
11:00   T. Foglizzo   Identifying the instability mechanism at work behind SASI    
13:30   J. Sato   Numerical investigation of SASI through a toy model    
14:30   E. Livne   Towards reliable simulations of core-collapse supernovae    
15:30       tea        
16:00   N. Ohnishi   Effects of neutrino heating and g-modes on SASI with steady-state initial conditions    

 Wednesday, July 2

9:30   S. Whitehouse   New results from 3-D supernova models with spectral neutrino diffusion    
10:30       coffee        
11:00   R. Käppeli   A Parallel 3D MHD code for core-collapse supernovae    
14:30   W. Iwakami   Numerical analysis of SASI by 3-D simulations    
15:30       tea        
16:00   S. Yamada   SASI in black hole accretion    

 Thursday, July 3

9:30   J. Margueron   Nuclear liquid-gas phase transition and supernovae evolution    
10:30       coffee        
11:00   B. Müller   O-Ne-Mg supernovae explosion dynamics and nucleosynthesis conditions    
14:00   C. Ott   2D multi-angle multi-group radiation-hydrodynamics simulations of postbounce supernova cores    
14:40   L. Dessart   Acoustic mechanism summary    
15:30       tea        

 Friday, July 4

9:30   C. Cardall   Magnetic field amplification by the stationary accretion shock instability    
10:30       coffee        
11:00   J. Guilet   Towards a MHD version of SASI    
13:30   M. Obergaulinger   Local simulations of the magneto-rotational instability    
14:30   T. Yamasaki   Effects of rotation on SASI & MRI during core collapse    
15:30       tea        


Monday, July 7

10:30       coffee        
14:30   M. Liebendörfer   Investigating supernova dynamics and magnetic fields in 3D      
15:30       tea        
16:00   H. Mikami   The 3D MHD effects for a core collapse supernova explosion    

Tuesday, July 8

9:30   Y. Suwa   Gravitational collapse of very massive stars    
10:30       coffee        
11:00   T. Takiwaki   Magnetorotational collapse and jet formation    
15:30       tea        

Wednesday, July 9

9:30   L. Dessart   Core-collapse supernovae explosions. Magneto-rotational mechanism    
10:30       coffee        
11:00   E. Audit   Radiation hydrodynamics using moment method    
15:30       tea        

Thursday, July 10

9:30   S. Scheidegger   The gravitational wave signature of 'realistic' 3D core collapse simulations    
10:30       coffee        
11:00   C. Ott   The gravitational wave signature of core-collapse supernovae    
14:30   K. Kotake   Stochastic features of gravitational-wave signals in 3D supernova explosions with SASI and GWs from MHD explosions    
15:30       tea        

Friday, July 11 

10:30       coffee        
11:00   T. Foglizzo   Concluding discussion        
15:30       tea        

Venue of the meeting

The address of IHP is 11, rue Pierre et Marie Curie, Paris 75005 (map of the area). More information about IHP can be found in English on their web page.

Desks and office space will be available at IHP for the invited participants, including iMac computers, printers, wireless and ethernet connection to the internet for personal laptops.

The first week (June 30 - July 4) will be organized with 4-6 talks per day, coffee breaks and time for discussions.
The second week (July 7-11) will offer more time for scientific interactions, with only 2 talks per day.

There will be no publication of conference proceedings, but the talks will be recorded and posted on the web server of CEA, together with their slides. This web page has been built with the kind help of C. Gouiffes.

Local Organizing Committee: T. Foglizzo, J. Guilet, J. Sato, T. Yamasaki.

Accommodation issues and financial support

Financial support will be granted to the invited participants who plan to also stay for the second week of the workshop. This support aims at covering the full cost of accommodation, either in apartments associated to IHP or in nearby hotels. 
Partial support for the first week will also be available upon application.
Student housing will also be available upon request, at the University Campus of the “Cité Internationale”.
A list of nearby hotels recommended by IHP is available here for those who can only stay for the first week. Early reservation is recommended, preferably before April 15.

Registration procedure for other participants

Researchers and students interested in attending this workshop are welcome.
Due to space limitations, registration by is recommended.




Last update : 09/19 2008 (2417)


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