radius orbit. The spring tension will increase as the two fluid elements move further apart and the process runs away.

It can be shown that in the presence of such a spring-like tension the Rayleigh stability criterion is replaced by
:Most astrophysical disks do not meet this criterion and are therefore prone to this magnetorotational instability. The magnetic fields present in astrophysical objects (required for the instability to occur) are believed to be generated via dynamo action.

Magnetic fields and jets

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