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Vlasov-Poisson : towards numerical methods without particles

June 1-12, 2015

Yukawa Institute for Theoretical Physics, Kyoto University


Vlasov-Poisson equations govern the dynamics of dark matter in the Universe as well as stars in galaxies. Traditionally, these equations are solved numerically by relying on a N-body approach where the phase-space distribution function is represented by a set of Dirac functions, that is an ensemble of particles. The discrete nature of this representation induces many defects in the simulations due, in particular, to N-body relaxation and to the shot noise of the particles. The goal of this workshop is to discuss and to work on state of the art methods to resolve numerically Vlasov-Poisson equations without resorting to particles. Semi-Lagrangian methods, widely developed in plasma physics, where the phase-space distribution function is represented on a grid, will be discussed and their application to the gravitational case will be studied. The cold case, particularly relevant to dark matter in the Universe, where the distribution function is supported by a smooth three-dimensional sheet evolving in 6-dimensional phase-space however deserves a special treatment, that will be discussed and studied as well. To best serve the purpose of this workshop, in the first two days of the workshop, a number of talks will be given by specialists on the subjects discussed just above, both in astrophysics and in plasma physics. In the remaining time of the workshop, current state of the art of the methods will be discussed and studied through ongoing and new collaborations.

Organizing committee:

Nicolas Besse, Stéphane Colombi, Yves Elskens, Isabelle Guillerme, Thierry Sousbie, Yasushi Suto, Atsushi Taruya

Contact address -> mailto:vlasov-poisson [snail] yukawa [period] kyoto-u [period] ac [period] jp

List of participants (and the title of their talk)


June 1
Auditorium of Yukawa Hall

9:30-9:50 : Welcome and registration

9:50-10:00 : Introduction
10:00-10:45 : Barnes

10:45-11:00 : Coffee break

11:00-11:30 : Fujiwara
11:30-12:00 : Elskens

12:00-14:00 : Lunch break

14:00-14:45 : Besse
14:45-15:15 : Hozumi
15:15-15:45 : Minoshima
15:45-16:15 : Madaule

16:15-16:30 : Coffee break

16:30-17:15 : Yoshikawa
17:15-17:45 : Sumiyoshi
17:45-18:15 : Deriaz

19:00 : Banquet

June 2
Auditorium of Yukawa Hall

9:45-10:15 : Abel
10:15-11:00 : Dubois

11:00-11:15 : Coffee break

11:15-11:45 : Peirani
11:45-12:15 : Nishimichi

12:15-14:00 : Lunch break

14:00-14:30 : Suto
14:30-15:00 : Touma
15:00-15:30 : Hallé

15:30-15:45 : Coffee break

15:45-16:15 : Angulo
16:15-16:45 : Hahn
16:45-17:15 : Sousbie
17:15-17:25 : Concluding words

June 3 - 12
Research building, rooms K102 and K202

Discussions, collaborations, informal seminars

June 4 :
15h30-16h30 : Informal discussion: Taruya (room K202)

June 5 :
14h00-15h00 : Yamaguchi (room K202)

June 10 :
14h00-15h00 : Informal discussion about Vlasov equations and galactic dynamics : Barnes & Touma (room K202)

June 11 :
14h30-15h30 : Colombi (room K202): post-collapse perturbation theory

Access to YITP

Details can be found here

The first 2 days of the workshop will take place in the auditorium of Yukawa Hall, while the remaining will be held in rooms K202 and K102 of the research building:

From Palace Side Hotel:


This workshop is sponsored by Yukawa Institute for Theoretical Physics through an International molecule-type workshop grant, by Agence Nationale de la Recherche through VLASIX project grant ANR-13-MONU-0003 and by Institut Lagrange de Paris.