From the linked question, we are assuming that a lightsaber is a tube-shaped magnetic field containing plasma. If this is the case, would a strong magnetic field generated by some outside source interfere with a lightsaber, possibly collapsing it and either disabling the lightsaber or allowing the plasma to diffuse in an unrestrained manner?
No. It should not be possible for an undirected magnetic field, external to a lightsaber, to be powerful enough to affect the plasma contained within nor the magnetic bottle formed by the lightsaber. Considering the history of the lightsaber and its manufacture having thousands of years of development and experimentation, it seem a reasonable assessment to assume a lightsaber would be stable under almost any condition or environment.
- Even the the material cortosis did not affect the blade, it attacked the energy cycle of the blade's power system, causing it to need to be reset after a few minutes.
Cortosis ore was a very rare, brittle, fibrous material whose conductive properties caused lightsabers to temporarily short out upon contact, although the wielder could solve this problem by turning the blade back on after a few seconds. This effect made cortosis a useful material for anti-lightsaber melee weapons, though with repeated strikes, a lightsaber could still cut through it. Cortosis, due to its heat and energy resistant properties, was also resistant to blaster fire.
For the record: Despite the claim of superconductivity loops only drawing power when cutting, there is no (known) explanation for how a lightsaber generates and maintains its prodigious energy output without an enormous powerplant. That said:
- Since the Republic/Empire is rife with advanced technology, there should certain be environments where strong magnetic fields should be found. We have never seen any circumstance where lightsabers do not work. In space, underwater, under blaster fire, through duranium doors, nothing seems to impede a lightsaber in progress, except another lightsaber. There may be a case for a very powerful force field since even the Jedi hate the droideka.
Often, Droideka were also equipped with deflector shield generators. These personal energy shields projected could endure much punishment, capable of deflecting or absorbing virtually any manner of energy or projectile fire up to the level of a light artillery bolt, as well as rebuffing lightsaber blades and physical attacks. The shields were powered by a starship-class fusion generator housed in a bulb at the junction of the droideka's legs. However, there was a weak point at the very top of the shield, a point where lightsabers would be able to penetrate.
- We are told the most dangerous time for a lightsaber is the initial creation of it. After that it is perfectly stable. Yet all of the parts are force-configured and force-tightened. The manufactured parts are Republic/Jedi created requiring the very specialized crystal to be activated.
This implies almost no force directed at a lightsaber can disrupt its mechanism, even another Force-user does not attempt to turn off a lightsaber. Knock it from a hand, yes. Cause it to stop functioning or unlock it's force-oriented configuration to cause it to malfunction? No. Never seen it. Either it is very difficult (impossible) or cannot be done as long as the Jedi who configured it is using it.
From purely an engineering standpoint, the lightsaber has to be a marvel of design. It is capable of holding intact a magnetic field of fiery plasma capable of melting steel, yet can be flung around a battlefield without fear of misfire or explosion. I have never seen a lightsaber explode during a fight. Considering even the Darksaber found after thousands of years in a vault being operational implies their design would be an engineering miracle by human standards.
The best answers I have ever found to how a lightsaber works is that it is contained plasma in an electromagnetic field. A simple EMP would disrupt this field, if even just temporarily. Even assuming the saber hilt was shielded from the EMP burst, the field itself would still suffer. Therefore, that is all that would be needed for a Jedi or Sith to have hot plasma flung all over them in an uncontained plume.
EMP's don't even need a nuke to go off to occur, as is a popular notion. look up the NNEMP