PPPL-5021


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<b>  What is the Fate of Runaway Positrons in Tokamaks?   </b>
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<b>Authors:</b> Jian Liu, Hong Quin, Nathaniel J. Fisch, Qian Tengk and Xiagang Wang
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<p><b>Abstract:</b> 
<br>   Massive runaway positrons are generated by runaway electrons in tokamaks. The fate of these
positrons encodes valuable information about the runaway dynamics. The phase space dynamics
of a runaway position is investigated using a Lagrangian that incorporates the tokamak geometry,
loop voltage, radiation and collisional effects. It is found numerically that runaway positrons will
drift out of the plasma to annihilate on the first wall, with an in-plasma annihilation possibility
less than 0.1%. The dynamics of runaway positrons provides signatures that can be observed as
diagnostic tools.
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Phys. Plasmas   <strong>21</strong> , 064503 (2014) </p>
<p>DOI: <a href="http://dx.doi.org/10.1063/1.4882435" title="Go to DOI for this Article">http://dx.doi.org/10.1063/1.4882435</a><br>
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  <a href="PPPL-5021.pdf"><b>Download PPPL-5021</b></a> (pdf 1.66 MB 12 pp)
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