Hall Thrusters

okay I think I have a basic understanding of the Hall Effect, but I need something more concrete and....

okay basicly can someone explain from nuts and bolts up how Hall thrusters work?

 

http://www.inspacepropulsion.com/tech/hall_thrust_physics.html

http://en.wikipedia.org/wiki/Hall_effect_thruster


Fly me too the moon... hahaha ''why not just google it''.. I should patent that phrase..

 

looked at those exact same pages, I didn't feel they gave an in depth enough explanation of the sciences and maths involved, I know that it basicly swims through the particles, pulls itself through by pushing stuff back, but I don't 100% get why


I'm trying to find the shortcut to that moment of realization I usually have a little while later.....

 

I just hope you don't turn out to be a mad scientist..spirited away to the middle east by evil dictators.. .. I dunno, good look with finding out though.. i merely am mortal.

 

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The Hall effect a transverse electric field seen when a current is passed through a metal in a magnetic field, the defining equation is below (vectors are a pain on these forums so a vector is a capital and a scalar is lower case so bare in mind x is the cross product NOT multiply).

E = rBxJ

E is the electric field due to the hall effect, r is the Hall coefficient, B is the magnetic field and J is the current density.
By applying a magentic field and a transverse electric field the Hall thruster has a rotating cloud of electons at the nozzle (outlet bit thingy, im not an engineer) these electrons are a Hall current (J from above, more or less) and are used to accelerate high molecular weight ions.

The maths isnt complicated its all F= BvIl and F=Eq its just getting your head around where all the charges go and the diagram on that wiki entry was pretty good i thought.

 

so instead of burning chemicals and forcing gas outward via the nozzle it forces the existing matter and forces it to move like a speaker's diaphragm moves air just on a much more impressive level

or like a rail gun moves metal it moves general purpose matter through itself just differently on an electromagnetic level

 

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Its a neat idea, I don know how a tank of fuel compares to a chemical engine but its another one of these where you need to be well away from the earth to use it. Its similar to the ion engine that I belive they snuck int star trek is impulse engines. Though they arent really that powerful which is a shame because the ions do glow very futuristically and it is a very tidy concept.

 

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