The Varney Prtocol [pressurized DPF system operating to 50 atmospheres].

[JVarney]

Total DPF system [excluding capacitors,switches, local panel and high integrity harness connecting to electrical infrastructure and site services systems] housed in pressure vessel that is filled will fill gas [fuel]. External components integrated into system via electrically insulated/ pressure containment connections thru vessel wall. The reactor [Cathode/Anode] recieves fill gas freely from pressure vessel.

System start-up [for a continuous power producing operation as an on grid fusion reactor] proceeds from an initial pressue of 0.03 atmos. gradually increasing to service pressure of 50 atmos. As pressure increases and retardation of plasma sheath formation along anode occurs, then electric charge events per plasma pulse [cycle] is incrementally increased from 1 to 2 then 3 and so on so that the accunulating electric charge energy matches the demand to maintain the pulse cycle at a specific and preferred frquency [with every stage of pulse being maintained in a healthy manner but perhaps at a reducing amplitude]. At each step change of charge frequency perhaps voltage adjustment will enable a close match of energy demand [for pulse] to be delivered. The external capacitor banks supplying the electric charge can be sequenced to maintain frequency range/ capacitor within an acceptable range.

With high pressure fill gas, the electron decelerator may be small and perhaps the Xrays emitted would be decelerated adequately thru gas before impacting the special panels lining the inside of pressure vessel wall for converting slowed Xrays into useful energy.

In order for the Ion Beam Decelerator to work efficiently and thus to generate a healthy gain ratio [output/input] for the fusion reactor, it needs to operate at a vacuum throughout the operation. By placing the ion beam delerator in its own [relatively small diameter] chamber but within the main pressure vessel, it can operate at a vacuum but its chamber will of course be subject to the compressive forces from the fillgas in the system pressure vessel. By installing an electro-magnetic sphincter at the entrance to the ion beam decelerator, the entrance will be snug around the ion beam during its existance and the entrance will be fully closed when there is no beam in existance. This arrangement allows the reactor to operate at service high pressure [and with extremely dense fusion formation] and allows decelerator to operate in a vacuum whilst preventing leakage of unburnt fill gas into the decelerator.
The ion beam may well [under service conditions] fluctuate in size [diameter] during the pulse cycle rather than appear and disappear and this feature could possibly be exploited to lead to more concentrated output.
The ion beam decelerator needs to be cooled as does the small quantity of unburnt fuel exiting via the vacuum line.
John Varney

[asymmetric_implosion]

50 atmospheres….wow. That is ambitious. Is this a real thing or an idea? I know shock plasma system operate in liquids and at high pressure but what is the advantage in a PF? To my knowledge the highest successful pinches are still well below atmospheric pressure at like 80 Torr. Most folks operated at more like 8 Torr. If real, what kind of current pulse is required?

[JVarney]

This is no more than a gut feel idea – but the extreme density of fill gas in which the plasma forms, travels down anode, does the horizontal mushroom dance and then collapses to the plasmoid generating the ion beam shot [the sequence being the pulse], the plasma density for that pulse time lapse, is a factor of 1000 times that currently and historically used in different versions of the DPF devices available.
This density should do the following:-

[a] Provide an environment for an enormous increase in fusion reaction flux for the brief period that temperature conditions allow [during collapse phase]
Cause, [because of high reaction flux], a prolonged decay of fusion friendly conditions that in effect will eventually lead to beam shot partially existing continuously but exhibiting, in concert with the preferred pulse cycle, a low amplitude cycle of beam strength that can be reflected in the actual [moment by moment] beam dia.

The challenge will then be to convert the beam energy [at all its varying stregths] in an improved decelerator/capacitor system including a simple cooling regime that is effective, safe and economical on coolant quantities.

The voltage and frequency requirements to satisfy the energy demand of the preferred pulse frequency, as one goes from initial start-up at say .03 atmos thru to service operation at 50 atmos., can only be accurately assessed thru experimentation.
John Varney

[asymmetric_implosion]

I’m not sure you can sustain the current pulse or more importantly the pinch/plasmoid for 1000X the time. The PF is by nature a fast pulse (~100 ns) event driven by instabilities in the plasma. To stabilize the pinch would eliminate some of the physics that makes efficient fusion possible. These instabilities are also driven by temperature of the plasma and the speed the plasma travels. By operating at 50 atm, you are likely to quash the conditions needed to generate fast ions. LPP operating at 80 Torr is a huge departure from normal PF operation of 1-20 Torr. I’ve seen mentions of atmospheric fill pressures in the long term but the jury is still out on an upper pressure limit. Plasma physics might not be kind enough to allow such high pressure fill. If I were to bet I would guess the operating reactor will be sub-atmosphere at room temperature. If heated the ambient pressure could be greater than atmospheric pressure.

Scanning the pressure to optimize radiation yield is commonly done by those that operate PF devices. Models and semi-empirical relations provide a bounding range but the pressure scan is essential to find the real answer.

[JVarney]

Thankyou for your take on my protocol.
I suspect you do not appreciate the intent of the strategy identified [ probably because of poor articulation on my account] so If I may, I will try to be more coherent in the following description:-

The 50 atmos is 1000 times the current upper limit of operating range of 0.03 to 0.05 atmos.
As retardation of plasma formation [movement along anode] is most likely in some mathmatical relationship with the fill gas pressure [linear or non-linear], then, at a preferred and pre-selected ion beam pulse frequency, one must apply sufficient energy to the plasma forming sheath to achieve the necessary velocity [of movement down a somewhat shortened anode] to maintain that pre-selected pulse frequency and thus the healthy transit thru each phase of its cycle.
As pressure of fill gas proceeds upwards from its initial start-up value of 0.05 atmos., the energy of the charge will be appropriately increased to maintain pulse rate of ion beam, by [a] increasing charge frequency i.e from 1 to 2 cycles, then 2 to 3 cycles, then 3 to 4 cycles and so on. at the same time, especially in the early stages of pressurization [i.e from 1 charge cycle to 2 charge cycles] by manipulating the charge voltage to obtain as good a match as possible between delivered and demand energy. In due course this difficult alignment of delivered and demand energies can be properly controlled with computor based signals [developed from experimentation with the DPF system].
We thus build pressure and maintain the time lapse between ion beam shots [pulse frequency]
It will be a learning process which will reveal the range of charge frequency and charge voltage required as pressurization proceeds. Note that multiple charge capacitors would enable [at higher charge frequencies] for each capacitor, via sequencing, to operate at more modest frequencies.
Now, as the flux of fusion events increases, the ion beam shot phase [of pulse cycle] will gradually last longer owing to lengthening decay time of conditions friendly to fusion events such that the beam shot still has its peak at pre-selected pulse rate but exhibits an after glow of decreasing strength. As one approaches target operating pressure [50 atmos.] it may be that there is no discernable gap between shots, only a shot profile that shows peaks at pulse rate with a decaying strength before rapid building to next peak.
None of us knows what will happen but the benefits of realizing a positive outcome are absolutely mind boggling and fully justify experimentation rather than searching for reasons for not trying [in accordance with pre-concieved notions of operational limitation].

John Varney

[asymmetric_implosion]

Plasma flow along the electrodes is described by a number of models. The most analytically tractable is the snow plow model. The models grow with complexity as detail is added. The most advanced models run on parallel computing systems taking hours to complete a full simulation. This models consider current, geometry, gas pressure and depending on the model, the fraction of the gas that is carried by the plasma. In a plasma focus, only a fraction of mass is actually carried by the plasma. All these models assume breakdown (plasma generation) is possible and meets certain criteria. Generating a plasma at 50 atmospheres is non trivial to say the least. There is a reason that plasmas are generated at low pressure.

The pressure is an important input in the electrode design. For a given set of electrodes and current, there is a unique optimum pressure. One can increase the current to increase the operating pressure but moving from 0.03 atm to 50 atm would require an increase in current from say 1 MA like FoFu-1 to 50 atm without changing the electrodes requires an increase in current by ~31X. To my knowledge, the peak current ever generated in a pulse power device is 26 MA at Sandia National Lab on the Z-machine. The down side is the Z-machine pulse will not work for a PF; it is 100 ns instead of the 1-2 microseconds more commonly used in a large plasma focus. Z stores 20 MJ to generate the pulse. For a PF you would need something like 10X the stored energy to produce a pulse that is 10X longer. If you want to extend the current pulse by 1000x, you need 10,000X the energy of Z or 200 GJ per shot. Power generation would need to be 3X more than the bank energy to be useful. A single shot that produces 600 GJ is not impossible but the system engineering is well beyond our abilities at this time. For perspective, the average power plant operates at 3 GJ per second thermal energy or roughly 1 GJ/s electrical. You could argue that you need to fire only once every 400 s to sustain this rate. The problem would be designing a system that could deal with such a peaked power generation cycle.

[JVarney]

Your presentation of data specifics, that have relevence to my pressurization strategy is certainly impressive in its complexity however, for my view, it paints a somewhat random and reluctant approach to a new way of thinking [that must, in order to proceed, concentrate on what can be attempted, rather than reasons for turning away from the challenge].

When starting a bold journey into the unknown, all who choose to participate, should ensure extensive and open debate to define as completely as is possible the realities that are percieved to exist, then within bold but prudent aspirations, proceed on the journey with a plan that embraces a theme of simplicity and incorporates an element of scientific beauty.

Thanking you for your expertise in the field [that far exceeds mine] I urge you to muster your enthusiasm for this opportunity [that I invite you to participate in] to venture forward with a courage which is tempered with prudence gained from your specialist knowledge.

John Varney

[asymmetric_implosion]

Your protocol moves into a realm of unexplored territory. Understanding the unknown is the heart of science and I believe experimental work is the key. However, enthusiasm must be tempered by technology; specifically, technology that is in reach. A comment that I’ve heard passed around for years in science is that cutting edge work is funded to attempt one miracle. Your protocol has at least two miracles in it. The first is the operating pressure. I think it is possible to build an experiment to test the pressure component at a few shots per day. The cost is the real issue. To drive a plasma at 50 atm, you would need a substantial capacitor bank. The electrodes could be designed but pressure seals that can operate from 0.03 atm to 50 atm are daunting. I don’t know if the technology exists. If someone knows of such a technology I would love to know about it. It would fix some of my problems in other projects.

The second miracle is operating the pulse power at the repetition rate you are implying. If I take your words in the most favorable way for the pulse power, it is a daunting pulse power system. If one starts with the assumption that you want to fire a pulse as soon as the gas in the pressure chamber is back in equilibrium after the previous shot (~1ms). A capacitor bank can be charged in 1 ms with the correct supply. It is not common but possible. The energy in the bank at a minimum would be the LPP bank or ~60 kJ. Charging the bank then takes an average power of 60 MW (average home is 20 kW so you need the equivalent power of 3000 homes). OK, still not impossible but I don’t want to pay for that electrical substation. Charging and discharging a capacitor bank of this magnitude at 1 kHz has never been attempted. The capacitors exist as do the switches but again cost is significant at $7000 per switch (100+ switches) and $300 per cap (>200 caps).

I will try to muster my enthusiasm, but the key questions are what is the budget for such an experiment and where is the money coming from? Just off the top of my head you are talking about $1M just to reproduce the LPP system. The high pressure testing would probably cost another $1-2M/yr in people/overhead for likely two years to build the experiment and test it. A materials budget of $500K/yr would probably be essential after the pulse power and other essential components are in place.

The high repetition rate system could cost 10-100X the FF-1 system in hardware. To run the experiments would probably cost $3M/yr or more in qualified people with overhead to answer the questions. If you envision the experiments on the smaller scale it could cost less, but I can’t see a program of less than $5M over 5 yrs to get the answers you are seeking. The potential pitfall for the PF is that at small scale you are unlikely to form a plasmoid.

If you consider these comments unenthusiastic, please understand that the money is likely the limiting factor. Given the current government funding climate, it is hard to imagine them investing in such an experiment. Private investors are clearly interested (LPP is an example), but this project starts off requiring more funding than LPP has now to complete their first stage. There are a number of serious technical challenges that need to be addressed. None of these are impossible but the return on investment might be poor and the technical challenges might mask the answer you desire.

If a funding stream has yet to be identified, time should be taken to identify a likely customer before sweating out the technical details. I have yet to encounter an investor or gov’t techie with a checkbook that needs >25% of the technical details in the first discussion. Big picture ideas are generally enough before a proposal (gov’t) or business plan (investor). If you are seeking a nights and weekend kind of commitment of people, it might be possible without funding just to fill in some technical details, but a serious set of experiments is out of reach. Most university PF devices fire a few shots per hour at most and privately held machines are harder to access without money.

If you tell me that money is no problem, more technical details can be worked out and a team of solid individuals could be identified to attempt such an experiment. I can provide a list of folks that are active in the community with the skills that you need.

[Author]

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