  We discuss the importance of large scale strong magnetic field in the removal
of angular momentum outward, as well as the possible origin of different kinds
of magnetic barrier in advective, geometrically thick, sub-Keplerian accretion
flows around black holes. The origin of this large scale strong magnetic field
near the event horizon is due to the advection of the magnetic flux by the
accreting gas from the environment, say, the interstellar medium or a companion
star, because of flux freezing. In this simplest vertically averaged,
1.5-dimensional disc model, we choose the maximum upper limit of the magnetic
field, which the disc around a black hole can sustain. In this so called
magnetically arrested disc (MAD) model, the accreting gas either decelerates or
faces the magnetic barrier near the event horizon by the accumulated magnetic
field depending on the geometry. The magnetic barrier may knock the matter to
infinity. We suggest that these types of flow are the building block to produce
jets and outflows in the accreting system. We also find that in some cases,
when matter is trying to go back to infinity after knocking the barrier, matter
is prevented being escaped by the cumulative action of strong gravity and the
magnetic tension, hence by another barrier. In this way, magnetic field can
lock the matter in between these two barriers and it might be a possible
explanation for the formation of episodic jet.
