Radiated energy fraction of SPI-induced disruptions at ASDEX Upgrade
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61389021%3A_____%2F25%3A00648043" target="_blank" >RIV/61389021:_____/25:00648043 - isvavai.cz</a>
Result on the web
<a href="https://iopscience.iop.org/article/10.1088/1741-4326/adcbc0" target="_blank" >https://iopscience.iop.org/article/10.1088/1741-4326/adcbc0</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1088/1741-4326/adcbc0" target="_blank" >10.1088/1741-4326/adcbc0</a>
Alternative languages
Result language
angličtina
Original language name
Radiated energy fraction of SPI-induced disruptions at ASDEX Upgrade
Original language description
Future large tokamaks will operate at high plasma currents and high stored plasma energies. To ensure machine protection in case of a sudden loss of plasma confinement (major disruption), a large fraction of the magnetic and thermal energy must be radiated to reduce thermal loads. The disruption mitigation system for ITER is based on massive material injection in the form of shattered pellet injection (SPI). To support ITER, a versatile SPI system was installed at the tokamak ASDEX Upgrade (AUG). The AUG SPI features three independent pellet generation cells and guide tubes, and each was equipped with different shatter heads for the 2022 experimental campaign. We dedicated over 200 plasma discharges to the study of SPI plasma termination, and in this manuscript report on the results of bolometry (total radiation) analysis. We found, that the amount of neon inside the pellets is the dominant factor determining the radiated energy fraction ( f rad ). Large and fast fragments, produced by the 12.5 ∘ rectangular shatter head, lead to somewhat higher values of f rad compared to the 25° circular or rectangular heads. This effect is strongest for neon content of ≲ 3 × 10 20 neon atoms ( f neon ≲ 1.25 % neon) injected, where a lower normal velocity component (larger fragments) seems slightly beneficial. While full-sized, 8 mm diameter, 100% deuterium ( D 2 ) pellets lead to a disruption, the 4 mm or shortened 8 mm pellets of 100% D 2 did not. The disruption threshold for 100% D 2 is found to be around 1 × 10 22 deuterium molecules inside the pellet. While the radiated energy fraction of non-disruptive SPI is below 20%, this is increased to 40% during the thermal quench and vertical displacement event phase of the disruptive injections. For deuterium-neon-mix pellets, f radvalues of ⩽ 90 % are observed, and the curve saturates around 80% already for 10% neon mixed into the 8 mm pellets ( 2 × 10 21 neon atoms).
Czech name
—
Czech description
—
Classification
Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
—
OECD FORD branch
10305 - Fluids and plasma physics (including surface physics)
Result continuities
Project
—
Continuities
I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace
Others
Publication year
2025
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
Nuclear Fusion
ISSN
0029-5515
e-ISSN
1741-4326
Volume of the periodical
65
Issue of the periodical within the volume
5
Country of publishing house
US - UNITED STATES
Number of pages
15
Pages from-to
056036
UT code for WoS article
001476013700001
EID of the result in the Scopus database
2-s2.0-105003695502