A robust disruption mitigation system (DMS) requires accurate characterization of key disruption timescales, one of the most notable being the thermal quench (TQ). Recent modeling of shattered pellet injection (SPI) into ITER plasmas, using JOREK and INDEX, suggests long TQ durations (6–10 ms) and slow cold front propagation due to the large plasma size. If validated, these predictions would have an impact on the desired pellet parameters and mitigation strategies for the ITER DMS. To resolve these questions, a database of SPI experiments from several small-to-large sized devices (J-TEXT, KSTAR, AUG, DIII-D, and JET) has been compiled under the auspices of the International Tokamak Physics Activity MHD, disruptions, and control topical group. Analysis of the energy loss duration (proxy for the TQ duration) with machine size is presented for both mixed neon/deuterium (Ne/D) SPI and pure deuterium (D) SPI. Several metrics for the energy loss onset (e.g. soft x-ray signal drop, dip, and radiation flash) were considered as the conventional metric, electron cyclotron emission, is often cut-off during SPI. Several scalings with different onset metrics showed an increase in energy loss duration with machine size. The energy loss duration was additionally shown to be a function of the ratio between the number of SPI neon atoms injected and the stored energy. Analysis of the pellet shard position relative to the cold front found that in larger devices, pellets are typically found inboard of the surface at the energy loss onset. Lastly, the delay between the pellet shards hitting the surface and the energy loss onset was additionally found to increase with machine size. This suggests that the pellet shards in large devices will penetrate faster and further than the cooling front.
堅牢な崩壊緩和システム（DMS）には、主要な崩壊タイムスケール、特に熱クエンチ（TQ）の正確な特性評価が必要である。JOREKおよびINDEXを用いたITERプラズマへの破砕ペレット注入（SPI）の最近のモデリングは、プラズマサイズが大きいために、TQ継続時間が長く（6–10 ms）、冷却フロントの伝播が遅いことを示唆している。これらの予測が検証されれば、ITER DMSの望ましいペレットパラメータと緩和戦略に影響を与えるだろう。これらの疑問を解決するために、J-TEXT、KSTAR、AUG、DIII-D、およびJETの小型から大型までの複数の装置におけるSPI実験のデータベースが、International Tokamak Physics Activity MHD, disruptions, and control topical groupの後援の下で編纂された。装置サイズに対するエネルギー損失継続時間（TQ継続時間の代理指標）の解析が、混合ネオン／重水素（Ne/D）SPIと純重水素（D）SPIの両方について示されている。電子サイクロトロン放射という従来の指標はSPI中にしばしば遮断されるため、エネルギー損失開始のいくつかの指標（例えば、軟X線信号の低下、