Letters of Intent received in 2016

LoI 2018-1975
Distributions and statistical mechanics in space plasmas

Topics

1) Kappa and other non-Maxwellian distributions: Origin, theory, and applications in space plasmas
2) Plasma processes and mechanisms related to the statistical mechanics of space plasmas
3) Linear/nonlinear waves and dispersion analyses, solitons, shocks, waves in dusty plasmas
4) Turbulence: Evolution, dynamics, and effects in space plasma processes
5) Observations of phenomena in space plasmas related to non-Maxwellian behavior

Rationale

Statistical Mechanics is used to determine how a particle system behaves when it resides at thermal equilibrium - the concept that any flow of heat (thermal conduction, thermal radiation) is in balance. When a particle system is at thermal equilibrium (typical behavior of earthy gases, e.g., the air), the particles are distributed in a very specific way: There are many particles with small velocities and very few with large velocities. It is possible to write a mathematical equation describing how many particles are found at each velocity; this mathematical expression is called a “Maxwellian distribution”. However, space plasmas are particle systems distributed such that there are more particles at high velocity than there should be if the space plasma were in equilibrium. The mathematical equation that is frequently used to describe the space plasma is called a “kappa distribution”.
Classical particle systems reside at thermal equilibrium with their velocity/energy distribution function stabilized into a Maxwell/Boltzmann form. On the contrary, space plasmas throughout the heliosphere and beyond, from the solar corona and wind, the cometary and planetary magnetospheres, to the distant heliosheath, are plasmas out of thermal equilibrium and characterized by a non-Maxwellian behavior, typically described by kappa distributions and combinations thereof.
The turbulence is interwoven with the kappa distributions and the plasma statistical mechanics. The probability distribution of the differences of characteristic variables of the space plasma is typically described by kappa distributions. Small scale turbulent fluctuations are described by kappa distributions that turn into a Maxwell distribution in larger scales. In addition, the role of turbulence is of fundamental importance to understand the mechanisms generating this non-Maxwell behavior. For example, the stochastic acceleration derived by whistler-mode turbulence can produce kappa distributions. Also, the nonlinear wave-particle interactions can lead to the electron kappa distribution function as a stationary asymptotic state in a weakly turbulent plasma.
Kappa distributions and non-equilibrium statistical mechanics in space plasmas have become increasingly widespread across space plasma physics with the publication rate following an ongoing remarkable growth. The proposed symposium will review and improve the physical underpinnings of kappa distributions and statistical mechanics in space plasma physics. This will be succeeded through the following goals:
1) Bring together international leaders, professors, scientists, researchers, and students, related to the studies of space plasma physics under the scope of statistical mechanics;
2) Announce recent scientific advances;
3) Improve our knowledge of the theory of kappa distributions and of their implications/applications in space plasmas through the following subjects: (i) Statistical framework of non-Maxwellian distributions; (ii) Types and formulations; (iii) Origin and generating mechanisms; (iv) Effects of non-Maxwellian distribution in plasma processes; (v) Applications of non-Maxwellian distributions in space plasmas.

This symposium as an opportunity of great educational and scientific importance that will enable essential coordination and cross-community stimulation, bringing the new generation of scientists in the center of the most recent advances in space plasma research.