The mark consists of a calculus equation consisting of the following symbols, described left to right, and top to bottom (where applicable): The first term, to the left of the equals sign, consists of the mathematical symbol der, derived from the Greek letter Delta, beside a capital letter "B", or Greek letter Beta; below these two characters is a horizontal line, creating a partial derivative expression with the der and lower case letter "t" below. It means the partial derivative of "B" with respect to "t". For the purposes of the equation "B" means magnetic field and "t" means time. To the right of the equals is a lower case Greek letter "Eta", which represents magnetic diffusivity; next to the "eta" is a nabla calculus inversion symbol (inverse triangle, or inverse upper case Greek letter Delta), followed by a European number two, raised to indicate exponent (i.e.: to the second power), immediately followed by another capital "B" character symbol; next to the "B" is a standard mathematical plus sign, indicating addition. The remaining characters/symbols are another nabla (inverse triangle), a standard mathematical times (multiplication) symbol, a left parenthesis, a lower case alphabetic script letter u (which for the purposes of the equation represents velocity), another times symbol, then another capital letter "B" (Beta), and finally a right parenthesis (closing parenthesis). Generally referred to as Dynamo theory, the equation describes a dynamo, or magnetic field generator.