3 ms·

From the article: Electron screening makes it seem as though the deuterons are fusing at a temperature of 11 million °C. In reality, the metal lattice remains m

by mpreda 5y ago

From the article: Electron screening makes it seem as though the deuterons are fusing at a temperature of 11 million °C. In reality, the metal lattice remains much cooler than that, although it heats up somewhat from room temperature as the deuterons fuse. Sounds pretty much the same as room temperature to me. Also the pictures with the experimental setup suggest that the glass does not melt, which is pretty cool.

gus_massa 5y ago
The part about "electron screening" makes no sense at all. The deuterium nuclei are in the slots between the erbium nuclei. Most of the electrons are very close to the erbium nuclei, so the slots where the deuterium nuclei are have a low electron density. Approximately the same density of an isolated deuterium atom, perhaps the double, but I doubt it's 10x higher. The orbitals of the electrons of deuterium are like 1000x bigger than the size of the nuclei. So once the incoming deuterium nuclei approach, it will be much closer to the target deuterium nuclei and it will not see the electrons. Note that most of the energy of the repulsion is when the nuclei are close, not when they are far away. The erbium are useful to keep a lot of deuterium together, but the electrons shelling is probably very small. The trick they use is to use a very energetic gamma rays that colides (indirectly) with one deuterium, and this deuterium is very fast that is the same effect you get when you have a very hot deuterium.
- phkahler 5y ago
  >> The trick they use is to use a very energetic gamma rays that colides (indirectly) with one deuterium, and this deuterium is very fast that is the same effect you get when you have a very hot deuterium. That notion of "hot" is not the norm. Most of us think in terms of temperature, not "energy". Would you want to get an X-ray if it were described in a way that sounded like high temperatures going to fry you? No. When the original cold fusion work was published, physicists across the board declared it impossible, insisting that high temperatures (and/or pressures?) were absolutely required for fusion to happen. The notion of a desktop fusion reaction was categorically ridiculed. Now it's OK so long as we change our conventional definitions to make those earlier denials not seem ignorant. BTW I'm not saying the origial CF worked, just that those rejecting it used words that would also exclude the possibility of LCF (or LENR or whatever we call it now).
  - gus_massa 5y ago
    > The notion of a desktop fusion reaction was categorically ridiculed. The fusor was invented in 1964 https://en.wikipedia.org/wiki/Fusor https://en.wikipedia.org/wiki/Fusor
adrian_b 5y ago
Much the same as room temperature is only the average temperature of the metal. The few irradiated deuterons and the products of their collisions have speeds (kinetic energies) many millions times higher than those corresponding to the room temperature. The average temperature remains low only because few nuclei take part in fusion. If they would succeed to make enough nuclei to take part in fusion reactions to produce more energy than consumed, it is not clear how great the average temperature of the metal would become. If the temperature of the metal would not increase excessively, that could happen only if most of the energy produced by fusion would be carried away by neutrons, which would be absorbed somewhere else, generating useful heat, but also creating undesirable radioactive waste. This approach is indeed very promising, but there are many problems that must be solved, so there is still no chance for a fusion reactor in only a few years.
- zardo 5y ago
  >it is not clear how great the average temperature of the metal would become. Certainly not above the melting point of the metal if the lattice structure is required to sustain fusion.

by mpreda 5y ago

gus_massa 5y ago

The part about "electron screening" makes no sense at all. The deuterium nuclei are in the slots between the erbium nuclei. Most of the electrons are very close to the erbium nuclei, so the slots where the deuterium nuclei are have a low electron density. Approximately the same density of an isolated deuterium atom, perhaps the double, but I doubt it's 10x higher. The orbitals of the electrons of deuterium are like 1000x bigger than the size of the nuclei. So once the incoming deuterium nuclei approach, it will be much closer to the target deuterium nuclei and it will not see the electrons. Note that most of the energy of the repulsion is when the nuclei are close, not when they are far away. The erbium are useful to keep a lot of deuterium together, but the electrons shelling is probably very small. The trick they use is to use a very energetic gamma rays that colides (indirectly) with one deuterium, and this deuterium is very fast that is the same effect you get when you have a very hot deuterium.

phkahler 5y ago
>> The trick they use is to use a very energetic gamma rays that colides (indirectly) with one deuterium, and this deuterium is very fast that is the same effect you get when you have a very hot deuterium. That notion of "hot" is not the norm. Most of us think in terms of temperature, not "energy". Would you want to get an X-ray if it were described in a way that sounded like high temperatures going to fry you? No. When the original cold fusion work was published, physicists across the board declared it impossible, insisting that high temperatures (and/or pressures?) were absolutely required for fusion to happen. The notion of a desktop fusion reaction was categorically ridiculed. Now it's OK so long as we change our conventional definitions to make those earlier denials not seem ignorant. BTW I'm not saying the origial CF worked, just that those rejecting it used words that would also exclude the possibility of LCF (or LENR or whatever we call it now).
- gus_massa 5y ago
  > The notion of a desktop fusion reaction was categorically ridiculed. The fusor was invented in 1964 https://en.wikipedia.org/wiki/Fusor https://en.wikipedia.org/wiki/Fusor

adrian_b 5y ago

Much the same as room temperature is only the average temperature of the metal. The few irradiated deuterons and the products of their collisions have speeds (kinetic energies) many millions times higher than those corresponding to the room temperature. The average temperature remains low only because few nuclei take part in fusion. If they would succeed to make enough nuclei to take part in fusion reactions to produce more energy than consumed, it is not clear how great the average temperature of the metal would become. If the temperature of the metal would not increase excessively, that could happen only if most of the energy produced by fusion would be carried away by neutrons, which would be absorbed somewhere else, generating useful heat, but also creating undesirable radioactive waste. This approach is indeed very promising, but there are many problems that must be solved, so there is still no chance for a fusion reactor in only a few years.

zardo 5y ago
>it is not clear how great the average temperature of the metal would become. Certainly not above the melting point of the metal if the lattice structure is required to sustain fusion.