Read this: Ripple current is the AC component of an applied source (often a switched-mode power supply) whose frequency may be constant or varying. Ripple current causes heat to be generated within the capacitor due to the dielectric losses caused by the changing field strength together with the current flow across the slightly resistive supply lines or the electrolyte in the capacitor. The equivalent series resistance (ESR) is the amount of internal series resistance one would add to a perfect capacitor to model this. Some types of capacitors, primarily tantalum and aluminum electrolytic capacitors, as well as some film capacitors have a specified rating value for maximum ripple current.

What is the name given to the amount of internal series resistance needed to add to an ideal capacitor model in order to represent the heat generated by dielectric losses?
What is the answer? (If it cannot be answered, return "unanswerable")
equivalent series resistance (ESR)