The Space Charge Density node adds an additional space charge density ρ, which appears on the right-hand side of Poisson’s equation. This feature is available when the Material model of its parent feature (Gas, Liquid, Solid) is Insulator or Charge transport with the checkbox Enable custom space charge density in addition to the predefined values selected.

Enter a value or expression for the Space charge density ρ (SI unit: C/m3). The default is 0 C/m3. You can also select the space charge density defined in the The Transport of Charge Carriers Interface, where additional charge carriers are solved.