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Helicity Thinkshop 3

CID: helicity thinkshop 3

Website hosted by: Nobumitsu Yokoi
Affiliation: University of Tokyo

Organizing institutions:

Institute of Industrial Science (IIS), University of Tokyo

Institute for Space-Earth Environmental Research (ISEE), Nagoya University

National Astronomical Observatory of Japan (NAOJ)

Other sponsor:

The Kajima Foundation

Main category: Natural Sciences (Astronomy)
Alternative category: Natural Sciences (Physics)

Conference/Workshop objectives:

Helicities (kinetic, magnetic, current, cross, etc.), as well as energies, are fundamental quantities of hydrodynamics (HD) and magnetohydrodynamics (MHD). In the presence of certain combination of anisotropies (caused by, e.g., rotation, gravity, magnetic fields, etc.), mirror and reflectional symmetries in HD and MHD turbulence are broken. Symmetry-breaking in turbulence is measured by pseudoscalars such as helicities, which represent the topological properties of turbulence. In helical turbulence, mean-field structures (global vorticity, mean magnetic field, etc.) can be generated through a dynamo action by turbulent motions. Therefore, the dynamic and magnetic activities of the Sun and stars are intimately related to turbulent helicities. These relationships have been extensively investigated, both theoretically and observationally.
    In the past, two Helicity Thinkshops, mainly on solar physics, were held in 2009 and 2013 at the National Astronomical Observatory of China (NAOC) at Beijing, China (Chair: Hongqi Zhang). They originated from a Chapman Conference on Magnetic Helicity in Space and Laboratory Plasmas held at Boulder, USA, in 1998 (Chair: Alexei Pevtsov). This time we organize a Helicity Thinkshop in Tokyo, Japan.

Aims and Topics:
The aims of this workshop (Helicity Thinkshop 3) are 

  • to share frontier knowledge on the topic of helicity stemming from observational investigations in astrophysics and geophysics, and from numerical simulations and experiments in fluids and plasmas;
  • to promote closer collaboration between different research fields involved in helicity studies (e.g., solar/stellar/geo, theory/modeling/experimental/observations);
  • to construct models of phenomena potentially influenced by helicity whose underlying physical mechanisms are not entirely understood.

Topics to be discussed include

  • insights on and estimates of helicity in the Sun and solar wind, helical structures on Earth and other astrophysical bodies, as well as in the fluid and plasma experiments;
  • role of helicities in solar and stellar flares and in coronal mass ejections with an emphasis on space weather phenomena and their coupling with the Earth environment;
  • role of helicities in dynamo theories and numerical modelling;
  • sources of helicities in astro/geophysical context;
  • future directions in helicity studies.

In order to enhance interdisciplinary communication, all speakers in Helicity Thinkshop 3 are expected to present their talks in plain, generic physics language.


  • Nobumitsu Yokoi: nobyokoi (at)
  • Kirill Kuzanyan: kuzanyan (at)

Tokyo (Japan)
Date: 19.11.2017 - 24.11.2017

Conference poster: Download poster here.

Local organizing committee:

Nobumitsu Yokoi (Chair, University of Tokyo), Shoji Koyama (University of Tokyo), Takashi Sakurai (National Astronomical Observatory of Japan), Yoichiro Hanaoka (National Astronomical Observatory of Japan), Masaoki Hagino (National Astronomical Observatory of Japan), Shin Toriumi (National Astronomical Observatory of Japan)