Talk:Hall effect thruster

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1 Disputed
2 problem with Image link
3 Private U.S. firms making a hall thruster tugboat
4 Consistent naming

[edit] Disputed

"HETs use the Hall effect to trap electrons and then use the electrons to ionize propellant, efficiently accelerate the ions to produce thrust, and neutralize the ions in the plume." This implies that the electrons that are trapped by the Hall effect neutralize the ions in the plume, which is not the case. The neutralizing electrons come from an external cathode, usually a hollow cathode or Lab6 cathode.

"the electrons essentially pull the whole thruster toward the ions and thus accelerate the spacecraft" -- I would reconsider this... it implies that the spacecraft would be accelerating towards the exhaust plume which is not the case. The spacecraft is accelerated away from the exhaust plume because of the momentum transfered to the exhaust.

I agree - I came to this page to present the same question. From http://www.daviddarling.info/encyclopedia/H/Halleffectthruster.htm : The axial electric field developed between the electrodes interacts with the radial magnetic field to produce, by the so-called Hall effect, a current in the azimuthal direction. This current, in turn, reacts against the magnetic field to generate a force on the propellant in the downstream axial direction. So it is the current generated by the rotating electron cloud that produces a solenoidal magnetic field that ...? - Leonard G. 03:26, 5 September 2006 (UTC)

Also, the ions are not unaffected by the magnetic field within the device, but as they are heavy relative to the electrons they would not form the spiraling cloud as do the electrons (but within that field thay should take a helical path). The solenoidal nature of the magnetic field from the rotating electrons should at most tend to focus the ions while the acceleration exterior to the device would be from the repulsive force between the electrons and the ions.- Leonard G. 03:39, 5 September 2006 (UTC)

So fix it! 199.67.140.84 13:48, 5 September 2006 (UTC)

Ageeing with the dispute, thrust is momentum transferred to the exhaust. Please let us know, too, if circulating electrons are performing the ionization as the Xe enters at the anode? May I suggest that one invokes a Lorentz-force argument to explain the electron orbits, rather than the somewhat cryptic ExB? 80.167.170.174 21:42, 5 September 2006 (UTC)

The original claim that "the electrons essentially pull the whole thruster toward the ions and thus accelerate the spacecraft" is in fact correct. It was not quite clear from the original discussion but the spacecraft is pulled toward the ions which are upstream of the "virtual grid" of electrons (i.e. still inside the discharge channel), which would accelerate the spacecraft in the correct direction-- away from the exhaust plume. However, the discussion of exactly where and how the force is applied to the spacecraft can be quite confusing to someone wanting a general description of a Hall thruster so it might be best left unsaid.

[edit] problem with Image link

The image link at the begininning is not showing right. I don't know enough to fix it myself--not an obvious typo in the syntax.

[edit] Private U.S. firms making a hall thruster tugboat

Recently announced, the two private firms Andrews Space and SpaceDev are developing a hall thruster tugboat named SmallTug. It will transport cargo and satellites to the L1 Lagrange point near the moon. Anyway, I see that the ESA is represented, so I thought that the U.S. mission deserved some representation. Can we add this as an external link?

(or perhaps Micro-X Spacecraft Bus http://www.andrews-space.com/content-main.php?subsection=MTA3) - U.S.Citizen

I agree with the concensus above. Newton got it right once agaian. The acceleration of the vehicle is equal and in opposition to the average acceleration of the deionized xenon exhaust. - U.S.Citizen.

Did you mean to put this in the "Disputed" section? You can add comments to a section by clicking the "edit" link at the top of the section. —Keenan Pepper 16:31, 10 September 2006 (UTC)