Sciencemadness Discussion Board - Extreme balloon height with hydride anionic gas?

Extreme balloon height with hydride anionic gas?

deltaH - 1-10-2013 at 03:28

I have this crazy idea that goes something like this:

You fill a balloon with hydrogen gas and tether it to the ground. You then run a rudimentary nickel thermionic emitter within the balloon’s interior (nickel coil heated white hot by an electric current and strongly negatively biased) for some time to generate hydride anions in the gas mixed in with the neutral hydrogen. Excess heat is dissipated by the wall of the balloon due to hydrogen’s excellent thermal conductivity.

Afterwards, you set the balloon adrift near either magnetic north or south. The payload is fitted with some means to vent hydrogen from the balloon in a controlled manner as the pressure drops to prevent the balloon from rupturing, but importantly, this vent has some kind of charged screening mechanism to hold back the negatively charged hydride anions while letting the neutral hydrogen pass through.

Over the magnetic north or south pole, earth’s magnetic field lines are concentrated and so the balloon experiences a force as a charged object in a magnetic field (due to the super light and charged hydride ions which now dominate its contents). As the balloon climbs to very high altitude, the air pressure drops strongly and so too does drag causing the balloon to increase its velocity. As the balloons radial velocity climbs, so too does its altitude and so the balloon spirals upwards to greater and greater heights. Could one potentially reach the ionosphere with such a balloon or even beyond?

Probably a dumb idea because of multiple fatal physics flaws, but a fun thought experiment, no?

Thanks, NVT

Nicodem - 1-10-2013 at 06:00

Quote: Originally posted by deltaH

Probably a dumb idea because of multiple fatal physics flaws, but a fun thought experiment, no?

So, you want a baloon filled with anionic particles in the gas phase and in the absence of couterions?

Not even writers of science fiction dare to resort to such fantasy constructs.
For the beginning, I suggest you to read about the Coulomb's law. Maybe then you will grasp the idea of what magnitude of force it takes to keep 1 g of charged hydrogen atoms separated 1 m from the opposite charge.

PS: Welcome to the forum, but please make sure you read the forum guidelines. When opening threads without references, please do so in the Beginnings section. For example, how is anybody going to know what do you mean by "rudimentary nickel thermionic emitter" if you don't provide a reference? Besides it would do you good to read about it yourself, as you seem to believe a negative charge there is created without charge separation.

deltaH - 1-10-2013 at 06:38

Hi Nicodem,

A thermionic emitter in the classical sense emits electrons, the positive charge left behind by this emission from a hot metal is quenched by fresh electrons supplied by whatever is supplying the negative bias. Thermionic emitters are named such in part because they apply in the general case and can be used to emit ions (besides for electrons). In this case, my thinking was that on the surface of hot nickel, hydrogen would be dissociated to surface hydride species (bound atomic hydrogen H*) then due to the high temperature and a negative bias, these bound surface atomic hydrogen can be 'boiled off' as their negative anion, instead of just the usual electrons being ejected off.

Are you saying that the number of hydride ions that one could generate in neutral hydrogen thus would be insignificant?

watson.fawkes - 1-10-2013 at 07:02

Quote: Originally posted by deltaH

Probably a dumb idea because of multiple fatal physics flaws [...]

The force from a magnetic field is always orthogonal to the field. The force from a vertical magnetic field (approximating the earth's poles) is parallel to the ground, providing no lift.

And if you're after a charged object, beaming electrons out directly is far easier.

Nicodem - 1-10-2013 at 07:14

Quote: Originally posted by deltaH

A thermionic emitter in the classical sense emits electrons, the positive charge left behind by this emission from a hot metal is quenched by fresh electrons supplied by whatever is supplying the negative bias.

In the case of charges, there is no such thing as "supplied by whatever". The charge that is emitted needs to come from somewhere and given that you start from a neutral system, the amount of negatively charged particles emitted need to be compensated by a potential that keeps the positive particles apart (see Coulomb's law). Charged particles are not just created from nothing. They are created by the charge separation. For example, a molecule can dissociate into a cation and an anion, an atom can be ionize into a cation and an electron, a neutron can decompose to a proton and an electron, etc., but you can't create a negative charge from nothing unless you create it together with a equal positive charge.
Besides, charged particles in the gas phase are unstabilized and can fly wherever they want to and deposit the charge on whatever can accept it.

Quote:

Are you saying that the number of hydride ions that one could generate in neutral hydrogen thus would be insignificant?

Insignificant is the correct word. Minuscule amounts of unbalanced anions is already enough to spark a lightning. Micrograms of confined charged particles should be enough to cause a huge explosion. And you talk about a baloon, which would be kilograms!

The density of hydrogen is already only about 7% of the air's density. It makes no sense to use any complicated system to gain a few more % of lift force.

deltaH - 1-10-2013 at 07:27

Quote:

And if you're after a charged object, beaming electrons out directly is far easier.

I am after generating hydride anions in the gas phase, not cations.

Quote:

The force from a vertical magnetic field (approximating the earth's poles) is parallel to the ground, providing no lift

Does an orbiting object not orbit higher and higher if you accelerate it?

Nicodem - 1-10-2013 at 07:42

Quote: Originally posted by deltaH

Quote:

The force from a vertical magnetic field (approximating the earth's poles) is parallel to the ground, providing no lift

Does an orbiting object not orbit higher and higher if you accelerate it?

But there is no acceleration in what you describe. A stationary charged particle does not accelerate in a homogeneous magnetic field, like the field near the poles. Only if the particle moves through the magnetic field, an orthogonal force acts on it. Small particles always move due to thermal energy, but objects like baloon don't move unless something pushes them (and they obey the Newton laws).
This means that an charged object moving from west to east (or opposite), somewhere near the equator, for example, would feel the acceleration in the upward or downward direction, by an equal deacceleration in the west/east direction. Therefore, the momentum would not be increasing.

deltaH - 1-10-2013 at 07:45

Quote:

The charge that is emitted needs to come from somewhere and given that you start from a neutral system, the amount of negatively charged particles emitted need to be compensated by a potential that keeps the positive particles apart (see Coulomb's law). Charged particles are not just created from nothing.

I am puzzled by this argument. Thermionic emitters have been used for over a hundred years now to generate charged beams of ions. The posative charge created on the metal by the removal of charge cause by either electrons being ejected or the special case of anions, is quenched by the power supply that maintains the negative bias. Once ejected, these anions are repelled by cathode (the hot metal from which it was ejected and kept at a negative bias).

Now as far as the charge leaking goes, it's important to remember what we are dealing with. A free gas phase hydride anion is a relatively stable 'animal'. It's 1s shell is complete and the electron is bound. The only thing that it sees is other hydrogen molecules, transferring an electron there would mean the following reaction:

H- + H2 => H* + H2-

This is energetically unfavorable. I am also under the belief that the spontaneous emission of the electron into free space is also energetically unfavorable, i.e. the process of:

H- => H* + e-

because you generate a radical, the 1s orbital is then incomplete and so this is a higher energy state

Nicodem - 1-10-2013 at 08:08

Quote: Originally posted by deltaH

The posative charge created on the metal by the removal of charge cause by either electrons being ejected or the special case of anions, is quenched by the power supply that maintains the negative bias. Once ejected, these anions are repelled by cathode (the hot metal from which it was ejected and kept at a negative bias).

I hope you realize the nonsense of what you said here. You seem to believe that the power supplies supply charges!
All that any power supply ever does is supplying electrical current, a current that is created by the electric potential (electromotive force) which is maintained by some energy source (chemical in bateries, mechanical in dynamos, etc.). In short, a power supply only moves charges, but cannot create them.

Quote:

A free gas phase hydride anion is a relatively stable 'animal'.

Do you have any references? Any at all? For any charged particle in the gas phase, or in any other medium of low relative permittivity?

[Edited on 1/10/2013 by Nicodem]

deltaH - 1-10-2013 at 08:42

Quote:

In short, a power supply only moves charges, but cannot create them.

Never claimed that they were created. The charge separation that you are looking for occurs at the metal surface. A surface bound hydrogen atom boils off with one too many electrons, hence a hydride anion, and it leaves a positive hole in the metal, the metal is one electron less. This is then quenched by fresh charge supplied by the power supply. charge was only moved overall. From the opening paragraph on the wiki article on thermionic emission I quote:

"The charge carriers can be electrons or ions, and in older literature are sometimes referred to as "thermions". After emission, a charge will initially be left behind in the emitting region that is equal in magnitude and opposite in sign to the total charge emitted. But if the emitter is connected to a battery, then this charge left behind will be neutralized by charge supplied by the battery, as the emitted charge carriers move away from the emitter, and finally the emitter will be in the same state as it was before emission."

Note that this applies to ions or emitted electrons and the replenishing of charge by the battery.

Quote:

Do you have any references? Any at all?...

I can refer you to the article "The Negative Ion of Hydrogen", A.R.P Rau, J. Astrophys. Astr. (1996) 17, 113–145 on the curious intrigues of the hydride anion in the gas phase, though I am no physicist and so would appreciate it if you would shed light on the matter.

Nicodem - 1-10-2013 at 09:10

The wikipedia quote is for an electrical circuit. You proposed an electrostatic device.

Quote: Originally posted by deltaH

Quote:

In short, a power supply only moves charges, but cannot create them.

Never claimed that they were created.

Quote: Originally posted by deltaH

Note that this applies to ions or emitted electrons and the replenishing of charge by the battery.

Seems like you need to make up your mind.

deltaH - 1-10-2013 at 09:13

Quote:

A stationary charged particle does not accelerate in a homogeneous magnetic field, like the field near the poles. Only if the particle moves through the magnetic field, an orthogonal force acts on it.

Please clarify for me, I do not understand how the particle can experience a force yet not be accelerated by it? Unless the force is cancelled out by another force, but what is this other force?

watson.fawkes - 1-10-2013 at 09:19

Quote: Originally posted by deltaH

Does an orbiting object not orbit higher and higher if you accelerate it?

You really need to learn about acceleration with vectors and not the simplistic 1-D version. The presence of a non-zero acceleration does not mean that the magnitude of the velocity must change. It always means, however, that the velocity vector changes somehow, either in direction or magnitude. With transverse acceleration, only the direction changes.

deltaH - 1-10-2013 at 09:21

Quote:

You proposed an electrostatic device.

No I did not, I stated that I would employ a thermionic emitter, these need to be run by a power supply. I never stated that magically 'hydride ions spring to life'

I believe I have made it quiet clear how such a thermionic emitter device operates and have provided resources for you in this regard as well as a reference about gas phase hydride ion behavior.

deltaH - 1-10-2013 at 09:38

Quote:

I am posting on this forum to discuss and learn! Anyhow, I think I understand what you are saying, let me state it in my own words to check my understanding. So the charged balloon, when moving may be deflected by earth's magnetic field which may make it travel in a circular path around the pole but there is no net force that either speeds it up or increases its height. The magnetic field merely deflects its path, yet it doesn't change it's altitude. So the balloon doesn't spiral upwards, it just spirals. With no net acceleration drag will slow it down ultimately and it must become stationary at some fixed altitude.

So the conclusion is that there is no 'significant' lifting benefit by replacing some hydrogen with hydride ions although there is the debate about whether they can be created in the first place?

[Edited on 1-10-2013 by deltaH]

Nicodem - 1-10-2013 at 10:10

Quote: Originally posted by deltaH

You then run a rudimentary nickel thermionic emitter within the balloon’s interior (nickel coil heated white hot by an electric current and strongly negatively biased) for some time to generate hydride anions in the gas mixed in with the neutral hydrogen.

You want to take neutral mater, separate into negative and positive particles, move them apart, maintain the negative ones confined physically and safe from discharging. That is definitively an electrostatic device.

Quote:

The magnetic field merely deflects its path

Yes, you got that.

Quote:

So the conclusion is that there is no 'significant' lifting benefit by replacing some hydrogen with hydride ions although there is the debate about whether they can be created in the first place?

No to the second part. The hydride ions can be formed. What I'm trying to explain you is that you can not have a confined, dense "gas" made of charged particles of the same polarity. The electrostatic repulsion between such a huge number of charged particles at close distance is immense. This is incomparable to a few distant hydride ions in the vacuum of the space, maintained solo by their kinetic energy and overall space matter neutrality. The vacuum of the space is neutral by average, there are positive and negative particles everywhere, while what you propose is something completely different. You actually talk about matter composed of uniformly charged particles. It is a reference to such kind of matter that I requested.

deltaH - 1-10-2013 at 11:12

Quote:

...can not have a confined, dense "gas" made of charged particles...

I understand that, my idea was to convert some of the hydrogen in a balloon to hydride ions, not the whole content in the hope of that this would decrease the density of the hydrogen. Let's for arguments sake say that my rudimentary thermionic emitter can work and starts converting some hydrogen molecules into hydride ions when you switch it on (on the ground presumably). As you run this, I would guess that unless there is a mechanism for neutralizing the hydride ions in the balloon quickly, then the hydrogen there would begin expanding as they feel the repulsive effect of the 'few' hydride ions among them?

Later, when the pressure drops, you can dump the bulk of those neutral hydrogen and keep just a very few of these hydride ions as presumably on can filter them out with something that acts as an electrostatic filter.

The second part of the idea was whether these charged ions could not contribute towards lift, but that has now been debunked, so that leaves the outstanding questions from the first part.

Quote:

The density of hydrogen is already only about 7% of the air's density. It makes no sense to use any complicated system to gain a few more % of lift force.

This I think is a point of interest worthy of further discussion. As I understand it, when it comes to reaching high altitude, mechanisms for decreasing the density of the lift gas are routinely employed, the simplest being heating the gas. The down side with heating is that you constantly have to heat and this is aggravated by the fact that the super light gases have particularly high thermal conductivity exacerbating your heating requirement problems. Also high altitude is really cold and that also exacerbates the problem.

Now while the 'thermionic emitter' may sound complicated, in it's simplest form, it's just an electrically heated coil attached to a high voltage power supply. As I see it, all that can stay on earth after the initial charging has been completed (note the charging is partial, only some hydride ions need to be formed to potentially have a big effect as you pointed out!).

But then again, I have no idea if forming some hydride anions would decrease the density of the bulk hydrogen?

Another interesting spin on this idea may be to use other gas that maybe isn't as light as hydrogen, but maybe less flammable but I can't think of another potentially suitable one that could easily be converted into stable enough anions? Maybe somebody can post suggestions for this if they exist.

Right now the only gas I can think of that could be 'anionized' like this is hydrogen and potentially this could be used as a way to lower it's density and gain lift without having to constantly heat it.

Nicodem - 2-10-2013 at 08:52

Quote: Originally posted by deltaH

Quote:

...can not have a confined, dense "gas" made of charged particles...

I understand that, my idea was to convert some of the hydrogen in a balloon to hydride ions, not the whole content in the hope of that this would decrease the density of the hydrogen.

It does not mater how much and at what partial pressure. It is not possible to maintain it dispersed in the gas phase like that. You keep on ignoring that these are charged particles and they obey the Coulomb's law.

Quote:

Let's for arguments sake say that my rudimentary thermionic emitter can work and starts converting some hydrogen molecules into hydride ions when you switch it on (on the ground presumably). As you run this, I would guess that unless there is a mechanism for neutralizing the hydride ions in the balloon quickly, then the hydrogen there would begin expanding as they feel the repulsive effect of the 'few' hydride ions among them?

There would be no such pressure, again due to the Coulomb's law. Charged particles in a sphere migrate to the walls where they form a capacitor. The pressure would be on the balloon walls, assuming it is made of an insulator, due to the strong electric field. As you would be pumping more and more charge into it (by increasing the potential), at some point the capacitor-balloon would give up and discharge. This would continue on and on, and that's just about all there would be occurring (such a device is also used as a toy and is called a plasma ball). The high hydrogen pressure would make it very difficult, if not impossible, to charge the balloon interior without applying dozens or hundreeds of kV of potential.

I'm not going to invest time commenting the rest of your "ideas", because it is obvious you are appear too disinterested in the real world (you don't care about the laws of physic) and scientific research (you don't argument with references or experiments).

deltaH - 2-10-2013 at 23:55

Nicodem,

It is off course your choice should you not wish to make replies in my thread. I have no problem with that. I do however have a problem with your tone, especially because you ARE a moderator.

Anyhow, as for you point of the hydride ions migrating to the surface interior of the balloon, that makes sense to me and point taken.

BTW I am not a physicist and my physics knowledge is highly limited, as I acknowledged in my opening post, this thread is a thought experiment, the purpose of which is to learn something by discussion. As watson.fawkes pointed out, nobody is obliged to participate, but you are obliged to maintain a civil tone if you do choose to participate, which you have not done.

bfesser - 3-10-2013 at 06:26

deltaH, there is nothing wrong with Nicodem's tone. What you suggest is impossible and he's been admirably patient with you.

Quote: Originally posted by deltaH

I have this crazy idea . . . Probably a dumb idea because of multiple fatal physics flaws.

If you wish to discuss whimsical ideas best categorized as fiction, request access to Whimsy. [closed]