Thoughts on RF, NMR, and a Farnesworth-based thruster

It may be difficult to separate "theory" from "application," but let''s see if this helps facilitate the discussion.
Post Reply
bigattichouse
Posts: 2
Joined: Tue Jul 02, 2019 12:48 pm
Real name: Michael Johnson

Thoughts on RF, NMR, and a Farnesworth-based thruster

Post by bigattichouse »

I've been working on an unrelated NMR/MRI project for a while now to learn more about how it works. It's led me down some thought experiments, but I don't have a fusor to test them.

In summary, when you get an MRI, Hydrogen ions in your body are held in a gradient magnetic field, to which an RF signal is pulsed at specific intervals. When the energetic H+ ions "relax" they release RF energy which is then processed by Fast Fourier to produce an image. If held at a constant, the frequency is ~42.5MHz/Tesla (This scales linerally). If pulsed at one frequency/field, and the field changes the relaxation pulse will happen at a new frequency depending on the new field. So if 1T field initially (42.5MHz), then the field changes to 0.5T, the relaxation will pulse at ~21.25MHz.

When these pulses occur, the H+ ions get "flipped over and lined up", and then a second pulse at 90 degrees forces them to sync rotations.

This started me thinking about Farnseworth Fusors, and if the fusion occurred when the H+ ions were perpendicular, parallel, or spin reversed. I know the H+ ions in the fusor are "orbiting", and I thought it might be interesting to see if a magnetic "tunnel" and RF signal tuned to the Larmor Frequency for H^2 (6.53566 MHz/T) might be able to enhance the fusion. By having a "tunnel" with the changing field as the ions orbit through the system, it might be possible to load the H^2 with energy in a lower state, and then force them into a stronger field when they release their energy - hopefully coinciding with fusion to cascade the effect.

So even if stuff under unity, I started thinking this might be an interesting way to create a Hall-Effect style thruster.. Sure - you're throwing off these ions, but if they travelled through a magnetic ring/tunnel, where you pumped them full of RF, the resulting fusion might help with energy transfer and thrust capability.

I realize this is a bit handwavy, but didn't know if anyone has tried overlapping RF+Magnetic fields in their fusors for an MRI-like effect.
User avatar
Richard Hull
Moderator
Posts: 14992
Joined: Fri Jun 15, 2001 9:44 am
Real name: Richard Hull

Re: Thoughts on RF, NMR, and a Farnesworth-based thruster

Post by Richard Hull »

Some interesting points, however at the amateur level the fields needed are more or less not available to even the well heeled amateur here. The actual work you might outline here would need millions to pursue actively even at the smallest scale with the vigor and commitment required to answer you surmise and musings to a scientific answer. It is understood you are just theorizing and that is what this forum is for.

Interesting theories of great complexity, even if they make sense, demand experiment to take forward to a real physical embodiment and that means money, a dedicated person, (spark plug, spearhead). If such a program is begun, as things start to gel, more money than originally predicted must be made available by an inspired source of the original capital provider. "Go fund me" efforts will not cut it.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
RobertMendelsohn
Posts: 85
Joined: Mon Jul 20, 2020 4:58 pm
Real name: Robert Mendelsohn

Re: Thoughts on RF, NMR, and a Farnesworth-based thruster

Post by RobertMendelsohn »

An interesting idea. +1 to what Richard said. At the temperatures in a fusor, the spin states will be evenly inhabited with only parts per million deviation. To examine polarization effects (i.e., what happens when the nuclei are aligned or anti-aligned), you need very low temperatures (on the order of Kelvins or milli-Kelvins) and strong fields (on the order of 10-30 Teslas) in order to get 70%+ in a particular spin state. Rather inaccessible to the [average] experimenter, but I hope someone tries it. If you do, please report back with what you find!
ChristofferBraestrup
Posts: 131
Joined: Sat Apr 11, 2020 9:47 am
Real name: Christoffer Braestrup

Re: Thoughts on RF, NMR, and a Farnesworth-based thruster

Post by ChristofferBraestrup »

Turns out fusion spin-dependence is a thing, though probably more so for D-T fusion, via spin-allowed/forbidden reactions.

Either way I found a pretty neat intro text on the subject, see below. maybe the sources it cites are more interesting than the text!


http://large.stanford.edu/courses/2011/ph241/ray1/

I think these studies might be better suited for accelerator based fusion than IEC or tokamak.
RobertMendelsohn
Posts: 85
Joined: Mon Jul 20, 2020 4:58 pm
Real name: Robert Mendelsohn

Re: Thoughts on RF, NMR, and a Farnesworth-based thruster

Post by RobertMendelsohn »

There may be a somewhat simple way of doing this (simple meaning in the tens of thousands vs. millions...); you could use a Stern-Gerlach apparatus to sort a small beam of tritium (illegal (with exceptions) and expensive) and then ionize it with a laser (two-photon process or VUV), this could then be accelerated and hit a polarized target (BoT). Not exactly beginner friendly!

But I appreciate that you are taking the time to really understand the fusion process (spin states are often overlooked) and thinking outside the box.
RobertMendelsohn
Posts: 85
Joined: Mon Jul 20, 2020 4:58 pm
Real name: Robert Mendelsohn

Re: Thoughts on RF, NMR, and a Farnesworth-based thruster

Post by RobertMendelsohn »

To add another thought, this is really important in measuring other nuclear reactions, and a lot of cross section measurements for fission (or other incident-neutron processes) are made using spin-polarized neutrons, and often spin-polarized targets. But as Richard pointed out, this is some *really* expensive gear.
User avatar
Dennis P Brown
Posts: 3159
Joined: Sun May 20, 2012 10:46 am
Real name: Dennis Brown

Re: Thoughts on RF, NMR, and a Farnesworth-based thruster

Post by Dennis P Brown »

Like all ideas, this is simply not based on careful thermo-dynamical considerations; what I mean is has the person calculated the cost in energy to polarize the spins for 10^17 ions? This applies to a thruster as well - more so, really. Then work backwards to determine the energy enhancement that such a process would need to achieve to make this economical? These are not overly difficult calculations for first order approximations (we will ignore the fact that spin alignment very well might provide no to little enhancement - that is an other issue and, as mentioned, could only be settled with experiment.) That they haven't performed these basic calculations means they are just throwing ideas out there and seeing what sticks to the wall, so to speak.
Post Reply

Return to “Fusor and/or General Fusion Theory (& FAQs)”