stability criterion condtion?why

Stability condition where? in what? for what?

please add more information.

Finite-Difference Time-Domain (FDTD).
The electric field is solved at a given instant in time, then the magnetic field is solved at the next instant in time, and the process is repeated over and over again.
In order to have an aquarate solution the grid should be crowded, let say Lamda/10.
Can you tell more about the stability?
The solution might mathematically oscillates if the steps are too long i think.

I want to konw the stability criterion condtion of 3-D cylinder ?
l find out two different stability criterion condtion ,i can't konw which is right?

I suggest you should read Taflove's book in Chapter 3 and 4.

Hi.best stability test in microwave is NDF