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I Proton- Proton Fusion on Earth?

  1. Jul 4, 2017 #1
    Hi, I have been doing my own personal fusion research for almost a year now and I recently began looking into the various fusion fuel cycles other than D-T and D-D. The cycle that I'm interested in is P-P fusion, I'm aware that this method is inefficient for energy production, however, it seems that P-P starts fusing at 15 million Kelvin in the sun (due to the sun's immense pressure). I am wondering what kind of energies you would require to fuse protium on earth using a vacuum and electromagnetic fields, say through the method of Inertial Electrostatic Confinement or Magnetic Confinement, as opposed to the extreme pressure and heat such as in the sun. Would you get the same results if you applied roughly 1300 volts (1300eV = 15,000,000 Kelvin) in a low-pressure atmosphere? Or would you need to apply a much higher potential?
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  3. Jul 4, 2017 #2


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    The energy is the same here on Earth as it is in the Sun's core. What's different is that the density of the Sun's core is so high that it can cause an appreciable amount of the incredibly rare p-p fusion events. More than 99.99% of collisions simply results in the decay of the diproton back into separate protons.
  4. Jul 4, 2017 #3


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    The reaction rate is something like a billion times lower than the DD or DT reaction rate. It depends on pressure and temperature of course, but the factor is so large that there is no realistic way to get any relevant pp fusion rate on Earth. The reaction rate is so small that I'm not even aware of experimental observations in the lab, because you are always swamped by side-reactions.
    Even if we could get the same collision rate as the Sun with its huge core pressure (we cannot): The power density in the core is just 40 W/m3, way too low to be interesting on Earth.
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