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I was watching a documentary and they were talking about causing fusion with laser( " over simplified " ) they have over 100 different lasers all low power like the power of a dvd player as they said but as the beams merge they are filled with a large amount of energy. That hits a hydrogen atom causing fusionn.

I don't think its just as simple as merging beams to get an enormous amount of energy so how did they do this? Can just merging laser beams into one really increase the energy. Can i do this on a much smaller scale?

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  • $\begingroup$ You probably can’t (unless you are a laser expert). The trick at NIF is it is a beam originating from one laser, yet amplified in many parallel sections, then recombined. $\endgroup$
    – Jon Custer
    Commented Nov 28, 2017 at 3:28
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    $\begingroup$ It is difficult to merge two weak laser beams into a stronger laser beam. But it is easy to shine one laser beam onto something, and cause it to heat up, then shine two laser beams onto it and cause it to heat up twice as much. Indeed, that result is guaranteed by conservation of energy. What they do at NIF is, of course, much more sophisticated, but as far as I understand it is a version of the latter. $\endgroup$
    – Rococo
    Commented Nov 28, 2017 at 4:04

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Inertial confinement fusion (ICF) is a type of fusion energy research that attempts to initiate nuclear fusion reactions by heating and compressing a fuel target, typically in the form of a pellet that most often contains a mixture of deuterium and tritium.

To compress and heat the fuel, energy is delivered to the outer layer of the target using high-energy beams of laser light, electrons or ions, although for a variety of reasons, almost all ICF devices as of 2015 have used lasers. The heated outer layer explodes outward, producing a reaction force against the remainder of the target, accelerating it inwards, compressing the target.

The objective is not to merge laser beams, but to heat up the outer layer of the material to be fused. It is an energy additive process, the way a tray of food will heat up twice as fast if two heat sources are underneath it.

Light in general carries power in the Poynting vetor, and energy is additive .

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  • $\begingroup$ Question, if i had 300 Watts i could use but divided then into 3 lasers all with 100W would it still heat it up faster then if i just had one laser using the full 300Ws? $\endgroup$
    – user176734
    Commented Nov 28, 2017 at 20:32
  • $\begingroup$ @user176734 Energy is a conserved quantity. Any difference in the rate of heating , either positive or negative would depend on the topology, for example the rate of black body radiation from the object might differ for different contact points of the laser beams. $\endgroup$
    – anna v
    Commented Nov 29, 2017 at 5:20

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