Flux is a simple and ubiquitous concept throughout physics and applied mathematics describing the flow of a physical property in space, frequently also with time variation. It is the basis of the field concept in physics and mathematics. There exist two common usages of the term flux, each with rigorous mathematical frameworks: For transport phenomena, flux is defined as a vector, whereas in electromagnetism, flux is a scalar quantity, as defined by the surface integral. The terms "flux", "current", "flux density", "current density", can sometimes be used interchangeably and ambiguously, though the terms used below match those of the contexts in the literature.

John Malloy AKA FLuX (born September 19, 1975) is an American fine artist, illustrator, designer, and sequential artist. His illustrations and designs have appeared in advertising, packaging, magazines, cd covers, apparel, on the web, and in posters, with clients ranging from Peace Tea to Diesel to Business Week. His fine art employs a variety of media, including pen & ink, oil & acrylic paint, and digital.