  Linear Induction Accelerator (LIA) is a unique type of accelerator, which is
capable to accelerate kiloAmpere charged particle current to tens of MeV
energy. The present development of LIA in MHz busting mode and successful
application into synchrotron broaden LIAs usage scope. Although transformer
model is widely used to explain the acceleration mechanism of LIAs, it is not
appropriate to consider the induction electric field as the field which
accelerates charged particles for many modern LIAs. Authors examined the
transition of the magnetic cores functions during LIA acceleration modules
evolution, distinguished transformer type and transmission line type LIA
acceleration modules, and reconsidered several related issues based on
transmission line type LIA acceleration module. The clarified understanding
should be helpful in the further development and design of the LIA acceleration
modules.
