  Aims. EXor-type objects are protostars that display powerful UV-optical
outbursts caused by intermittent and powerful events of magnetospheric
accretion. These objects are not yet well investigated and are quite difficult
to characterize. Several parameters, such as plasma stream velocities,
characteristic densities, and temperatures, can be retrieved from present
observations. As of yet, however, there is no information about the magnetic
field values and the exact underlying accretion scenario is also under
discussion.
  Methods. We use laboratory plasmas, created by a high power laser impacting a
solid target or by a plasma gun injector, and make these plasmas propagate
perpendicularly to a strong external magnetic field. The propagating plasmas
are found to be well scaled to the presently inferred parameters of EXor-type
accretion event, thus allowing us to study the behaviour of such episodic
accretion processes in scaled conditions.
  Results. We propose a scenario of additional matter accretion in the
equatorial plane, which claims to explain the increased accretion rates of the
EXor objects, supported by the experimental demonstration of effective plasma
propagation across the magnetic field. In particular, our laboratory
investigation allows us to determine that the field strength in the accretion
stream of EXor objects, in a position intermediate between the truncation
radius and the stellar surface, should be of the order of 100 gauss. This, in
turn, suggests a field strength of a few kilogausses on the stellar surface,
which is similar to values inferred from observations of classical T Tauri
stars.
