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[JimmyT]

How did you come up with 43% efficiency?

An article on the Focus Fusion site states 80% efficiency is expected.

LPP Team Starts Looking at Ion-Beam Energy Extraction
by Admin on Mar 31, 2007 at 08:27 AM

Energy from the plasma focus will be delivered in two forms a burst of x-rays and an intense beam of ions. Extracting the energy from the x-ray burst by photoelectric means has been outlined in our patent application and it seems that a high efficiency, around 80%, will be achievable. We have now started to look at the questions related to extracting energy from the ion beam.

Since the ion beam is a pulse of current, the best way to extract energy from it is inductively, by essentially the same process that makes a transformer work. The changing magnetic fields produced by the rapidly varying currents generate electric fields that can move electrons in a coil. The energy in the current can then be captured in a capacitor. As the beam exits the coil, rapid-acting diamond switches can open the circuit to prevent the energy from leaving the capacitors.

However, the challenge in this process is that the electrons in the gas that the ion beam passes through are also capable of carrying the return current by moving in the same direction as the ions. If the electrons within the beam itself carry this current, it will short out the coil and no energy will be derived from the beam.

A preliminary analysis of this problem is now being carried out by Eric Lerner in cooperation with Dr. Roberts Terry of Naval Research Lab and Dr. John Guillory of George Mason University. We are just beginning this work, but a review of studies in the literature has come up with some initial encouragement. First studies performed at Sandia Laboratory in the 1990�s showed that when the density of the gas and the density of the beams are close, the beam can propagate in a self-pinched mode that preserves the ion current and prevents most of the electrons from catching up with the beam. This is because it is more difficult for electrons to move across magnetic field lines than along them. Other studies showed that if a coil or other conductor is placed close enough to a self-pinched beam, the return current will flow preferentially through the coil rather than the plasma.

We will continue to study this issue in greater depth. As our experiments develop they will also shed light on the ion beams, whose current is measured with a Rogowski coil.

https://focusfusion.pmhclients.com/index.php/site/article/lpp_team_starts_looking_at_ion_beam_energy_extraction/

Roger,

You are only examining the last step of the pulse. Examine too, the first shake or two of each pulse.

Start at the beginning of the process where the capacitor’s discharge form an arc to the central electrode and end up forming a plasmoid . How efficient is this first step? In the Texas A&M;experiment the answer was 0.01%. That’s 0.0001 of the input energy. The extra energy ends up heating the central electrode. Which is why the issue of heat buildup is so critical.

The necessary minimum efficiency of this step for the overall process to work (to achieve actual break even) is around 53%. I’m not sure what efficiency Eric used in his computer simulations. I Believe the efficiency he assumed is 60%. Just from playing around with the numbers.

The overall thermodynamic efficiency is then calculated as:

_______electricity generated ______________
electricity generated + waste heat (From all steps)

Higher efficiencies in the first step will result in dramatically higher overall efficiencies, greater output per each unit, less waste heat, and lower costs per unit of energy generated..

Let’s pray Eric and his team gets the 60% he is seeking, or greater.