Itot

Itot, typically written I_tot or Itot, is a symbol used in physics and electrical engineering to denote total current in a circuit, system, or device. In circuit analysis, Itot represents the algebraic sum of currents at a junction or the current through a particular component when applying Kirchhoff’s current law: Itot = sum of branch currents. Currents are assigned a sign according to a chosen reference direction, and Itot captures the net flow of charge at a node or through a branch.

In three-phase power systems and power electronics, Itot may denote the total input current drawn by a converter or the current carried by a conductor, with the exact meaning depending on the convention used in a given circuit diagram or model. Because notation varies, Itot should be defined within each work.

In plasma physics, Itot is the total plasma current in magnetic confinement devices such as tokamaks. It is a crucial control parameter that interacts with magnetic fields to shape the q-profile and confinement. Large devices operate with Itot on the order of megamps; for example, ITER targets about 15 MA of plasma current, while existing tokamaks typically run a few MA.

In summary, Itot is a context-dependent notation for total current, and its precise definition depends on the discipline and the specifics of the model or circuit being described.