Note: Basic assumptions

Lets assume electromagnetic field described by electric and magnetic vector fields ${\displaystyle {\vec {E}}({\vec {r}}),{\vec {B}}({\vec {r}})}$ and plasma described by probability density ${\displaystyle f({\vec {r}})}$. Also lets assume that basic terms are self-explaining.

Definition: Magnetic vessel

Magnetic vessel is electromagnetic field device aimed for plasma keeping.

Definition: Linear configuration

Linear configuration of magnetic vessel is electromagnetic field with parallel field lines and open ends.

Definition: Toroidal configuration

Toroidal configuration of magnetic vessel is toroidal electromagnetic field with closed ends.

Definition: Number 8 configuration

Number 8 configuration of magnetic vessel is crossed electromagnetic field with closed ends and field lines in number 8 shape.

Definition: Stelarator

Stelarator is axial asymmetric magnetic vessel with toroidal configuration.

Definition: Poloidal magnetic field

Poloidal magnetic field of toroidal magnetic vessel is magnetic field component with field lines closed perpendicular around coordinate ${\displaystyle \varphi }$.

Definition: Toroidal magnetic field

Toroidal magnetic field of toroidal magnetic vessel is magnetic field component with field lines closed perpendicular around coordinate ${\displaystyle h}$.

Definition: Main axis

Definition: Magnetic axis

Definition: Major radius

Major radius ${\displaystyle R_{0}}$ is distance between main axis to magnetic axis.

Definition: Minor radius

Minor radius ${\displaystyle r_{0}}$ is distance between magnetic axis and plasma edge. (plasma edge definition needed, maybe 1/e drop of f(r)?)

Definition: Aspect ratio

Aspect ratio ${\displaystyle a}$ is ratio of major radius and minor radius

${\displaystyle a={\frac {R_{0}}{r_{0}}}}$