How do magnetic fields provide thermal insulation

Ian_Brooks

some Fusion power experimental reactors use tokamaks to contain plasma using strong magnetic fields. However this plasma is at a sizzling 1M Kelvin so how is this level of thermal insulation engineered, using magnetic fields?

mgb_phys

The magnetic field doesn't provide insulation it simply holds the electrically charged plasma away from the walls.
Heat isn't the same as temperature, the sparks from a sparkler are at >1000 deg C but don't contain very much heat.

*Bob S*

The plasma is primarily ionized particles. The Lorentz force is
F = q(E + v x B)
where q is particle charge, v is particle velocity, and B is magnetic field. The v x B term causes the ionized particles to move in orbits perpendicular to the magnetic field, similar to ions in a cyclotron.

Ian_Brooks

then what stops the core from melting? i'm certain plasma would be quite hot

Topher925

What stops the core from melting is that heat doesn't transfer at a high enough rate form the plasma to the core. Convective and conductive heat require a medium for transport. I'm not sure about the magnitude of radiative heat transfer from plasma though but I would assume the walls of the reactor would have a very low emissivity.

mgb_phys

The tokamak is a donut shape. The plasma is in a ring inside the donut in a very high vacuum it doesn't (ideally) touch the inner or outer walls.

*Bob_for_short*

Quote by Ian_Brooks

some Fusion power experimental reactors use tokamaks to contain plasma using strong magnetic fields. However this plasma is at a sizzling 1M Kelvin so how is this level of thermal insulation engineered, using magnetic fields?

Strong magnetic field provides physical separation of the plasma tore and TOKAMAK walls. Plasma itself at these densities and temperatures is not quite transparent for the "light" - it radiates mostly from its surface.

Bob_for_short.

Similar Threads for: How do magnetic fields provide thermal insulation
Thread	Forum	Replies
how do TOKAMAK's provide thermal insulation	High Energy, Nuclear, Particle Physics	2
Way To Test Thermal Insulation	Classical Physics	0
magnetic insulation	Materials & Chemical Engineering	5
Magnetic fields inducing electric fields - turning on lightbulb with magnetic field	Introductory Physics Homework	3
High Temeprature Thermal insulation	General Physics	2

Ian_Brooks	How do magnetic fields provide thermal insulation Tweet some Fusion power experimental reactors use tokamaks to contain plasma using strong magnetic fields. However this plasma is at a sizzling 1M Kelvin so how is this level of thermal insulation engineered, using magnetic fields?

mgb_phys Recognitions: Homework Help Science Advisor	The magnetic field doesn't provide insulation it simply holds the electrically charged plasma away from the walls. Heat isn't the same as temperature, the sparks from a sparkler are at >1000 deg C but don't contain very much heat.

Bob S	The plasma is primarily ionized particles. The Lorentz force is F = q(E + v x B) where q is particle charge, v is particle velocity, and B is magnetic field. The v x B term causes the ionized particles to move in orbits perpendicular to the magnetic field, similar to ions in a cyclotron.

Topher925	What stops the core from melting is that heat doesn't transfer at a high enough rate form the plasma to the core. Convective and conductive heat require a medium for transport. I'm not sure about the magnitude of radiative heat transfer from plasma though but I would assume the walls of the reactor would have a very low emissivity.