Talk:Hall-effect thruster

Reference to the Hall Effect
There is no reference in the article as to why the Hall Effect Thruster is so named. IMO there should be a reference to the Hall Effect and a link to the Hall Effect article in Wikipedia (http://en.wikipedia.org/wiki/Hall_effect). Tony (talk) 13:38, 21 June 2010 (UTC)


 * Now the Operation section says "This orbital rotation of the electrons is a circulating Hall current, and it is from this that the Hall thruster gets its name. " (with no reference). Hall effect does not mention Hall current. - Rod57 (talk) 01:22, 19 September 2020 (UTC)

Force?
In the intro, it says it generates about 1N of force. Later, it says it only typically produces 80mN of force...

Is one of these more correct, or are we dealing with different contexts? Please clarify 192.91.147.35 (talk) 15:44, 16 April 2010 (UTC)

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.

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.

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)

Consistent naming
I propose consistently using "Hall thruster" (no cap T) throughout the article. Any disagreement? Sdsds 22:54, 24 March 2007 (UTC)
 * How about changing the article title to reflect this? The article is called Hall effect thruster, whereas it should be Hall thruster to be self consistent. Hall effect thruster should be maintained as a redirect. 59.167.18.132 14:34, 28 August 2007 (UTC)
 * I'm glad the article is still called Hall-effect thruster as that is surely the proper name. 'Hall thruster' seems a lazy and misleading contraction, as Hall discovered the effect rather than inventing the thruster ? - Rod57 (talk) 01:29, 19 September 2020 (UTC)

Diagram seems incorrect
Unless this is a different version of the hall effect thruster or something, the outer coil looks wrong to me.

See:

The outer coils should go around the outside of the magnetic material.

Also see: (although less clear, the windings aren't topologically the same as our diagram).

Also the wiki diagram doesn't show the radial field lines at all.WolfKeeper 18:41, 28 August 2007 (UTC)

The whole point is that the outer ring needs to be a north pole, and the inner ring a south pole (or vice versa) to get a radial field, that's not really what our diagram shows.WolfKeeper 18:44, 28 August 2007 (UTC)

Glowing discharge channels in picture?
I've seen a lot of Hall thrusters and I've never seen them appear to glow as they do in the image of the Russian SPT's. Is there blacklight illumination in that picture, were the thrusters running on some kind of bizarre luminescent fuel, or is this just a case of some bad photoshopping?

The image is from NASA, and those are real thrusters, but the lighting arrangement is just too strange. I'd vote for some more normal images to replace it. —Preceding unsigned comment added by 141.212.57.239 (talk) 17:02, 10 September 2009 (UTC)

New tiny 2000-3500s thrusters for CubeSats

 * http://web.mit.edu/newsoffice/2012/microthrusters-could-propel-small-satellites-0817.html
 * http://web.mit.edu/aeroastro/labs/spl/research_ieps.htm

Someone should add those. In the hoped-for replenishable propellant (e.g. comet ices or Titan nitrogen) future, replacing the element is going to be a useful tradeoff with specific impulse, which means tiny is great. 71.212.250.193 (talk) 07:48, 18 August 2012 (UTC)

Consumption question
Could somebody clarify the consumption rate for Xenon during thrusting? That really is not clear in the "operation" section. Thanks! — Preceding unsigned comment added by 166.102.136.6 (talk) 14:22, 9 May 2017 (UTC)

Could mention X3 hall-effect thruster in development
Could mention X3 hall-effect thruster in development etc ? - Rod57 (talk) 01:11, 19 September 2020 (UTC)

Inconsistent use of Hall-effect thruster / Hall thruster
The first paragraph tells us that it is called a Hall-effect thruster, and mentions that it's sometimes called by other, similar terms such as Hall thruster. After the opening section however, almost the entire rest of the page (including two section titles) uses the term Hall thruster. Wouldn't it be better if all instances of 'Hall thruster' (after the first) were fixed up to be 'Hall-effect thruster'?

Out of Date
This wiki is rather out of date now and as mentioned previously is missing private companies that have been researching or testing them. 2A02:C7F:501E:3B00:900D:D18A:4E1E:404D (talk) 06:32, 7 December 2021 (UTC)

Are wall-less Hall thrusters the same as external discharge thrusters
talks of "wall-less Hall thrusters". Are they the same, just from a different maker ? - Rod57 (talk) 14:30, 29 December 2021 (UTC)

That ref also talks about benefits of a segmented electrode, eg. in reducing "breathing mode oscillation". - Rod57 (talk) 14:32, 29 December 2021 (UTC)

Krypton
In the section on Krypton, I note: [...ionization potential...] This means that thrusters utilizing krypton need to expend a slightly higher energy per molecule to ionize, which reduces efficiency. Additionally, krypton is a lighter molecule, so the unit mass per ionization energy is further reduced compared to xenon. Referring to "molecules" of Xenon or Krypton strikes me as odd, usually that term is reserved for multi-atom compounds. If nobody objects or beats me to it, I'll change that to atoms in a few days. Tarl N. ( discuss ) 03:55, 16 May 2022 (UTC)
 * However, these noble gases are still ionized during their time in the thrusters. It is as if the original editor thought of them as molar objects (one mole being 6.02214076×10^23 ions), after which they "return" to a neutral state (where would the electrons come from? There must be a distribution of velocities?). --Ancheta Wis    (talk  &#124; contribs) 11:37, 16 May 2022 (UTC)
 * See Ionization energy : The unit conversion is 1eV = 96.485 kJ per mol)
 * The editor thinks in eV. I am replacing the instances of "molecule" to "ion" --Ancheta Wis   (talk  &#124; contribs) 11:37, 16 May 2022 (UTC)
 * Thanks, that's better than what I was planning. Tarl N. ( discuss ) 19:34, 16 May 2022 (UTC)

Cathode in diagram
I hope I am doing this correctly as it is my first comment in Wikipedia. It would really help to understand the function of the Hall thruster if the diagram would clearly label the cathode. I'm a physicist and go to the diagram first, to see if I can make sense of it. There is a label "cathode neutralizer" but it is not clear if that is the same as the cathode. Jdibbl (talk) 13:39, 27 December 2022 (UTC)