Timeline for How do alpha particles heat the plasma in tokamaks and what does that trajectory look like?
Current License: CC BY-SA 4.0
13 events
| when toggle format | what | by | license | comment | |
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| Aug 5, 2022 at 16:31 | comment | added | WillWillCUB | @annav That doesn't really help, unless you point out where I was wrong. Nowhere did I say energy is not conserved. | |
| Aug 5, 2022 at 14:05 | comment | added | anna v | Your kinematics is wrong, Energy is always conserved, you just need the proper maths | |
| Aug 5, 2022 at 13:22 | comment | added | WillWillCUB | @annav If that were true then you're claiming that the 3.5 MeV of the alpha is negated by the magnetic field, and that there is no heating. And there is flow, which is what the plasma current is. The plasma current, mediated by the FLOW of electrons and ions, gives rise to poloidal fields. | |
| Aug 5, 2022 at 3:02 | comment | added | anna v | The instantaneous momentum of the creation of alpha will be overcome by the magnetic field created forces on the positive charge, there is no flow | |
| Aug 4, 2022 at 19:24 | comment | added | WillWillCUB | @annav The problem is that half of the alphas will initially move with some velocity opposite to that of the rest of the positive ions. Tke two extreme cases: D-T fuse and create an alpha and neutron. Case 1 the alpha is shot off perfectly parallel to the D-T ions and therefore transfers all its energy to them. Case 2 the alpha is shot off perfectly opposite to the D-T ions and therefore slows them down, or at least sends the ions in the opposite direction as well. The magnetic field is used to keep ions flowing in one direction, but not the other. | |
| Aug 4, 2022 at 19:11 | comment | added | anna v | The alpha particles have a charge of +2, en.wikipedia.org/wiki/Alpha_particle they are ions and have to follow the rest of the positive ions of the plasma. that they might get a random momentum perpendicular to the plasma current will just give a spread in that direction | |
| Aug 4, 2022 at 18:42 | comment | added | WillWillCUB | @annav I guess I meant that in the fusion reaction, the resulting particles will fly off in all directions. Some of the alphas will move with velocity parallel to the directions that the Deuterium and Tritium are moving. Some of the alphas will move in the opposite direction. The ones moving in the opposite direction will presumably slow down any ions they collide with. This is what I'm confused about still. I will do some calculations, but maybe there is a solution in considering that heating occurs via electron-ion collision, and that the alpha particles move slower than the electrons. | |
| Aug 4, 2022 at 7:14 | answer | added | Jean Jacques | timeline score: 1 | |
| Aug 4, 2022 at 4:48 | comment | added | anna v | @WillWillCUB "I suspect that half of the alpha particles will move in the negative direction of the plasma current," this is wrong, the charge of the alpha does not change! | |
| Aug 4, 2022 at 4:07 | comment | added | anna v | this earlier iopscience.iop.org/article/10.1088/0029-5515/40/1/307/pdf | |
| Aug 4, 2022 at 4:01 | comment | added | anna v | iopscience.iop.org/article/10.1088/0029-5515/40/1/307 | |
| Aug 3, 2022 at 22:44 | comment | added | David White | Since the alpha particles represent fusion "ash", I'm wondering how they are removed from the plasma. For any responders, I would appreciate you including that detail in your answer. | |
| Aug 3, 2022 at 17:44 | history | asked | WillWillCUB | CC BY-SA 4.0 |