Healing plasma current ramp-up by Nitrogen seeding in the full Tungsten environment of WEST

Achieving a successful plasma current ramp-up in a full Tungsten tokamak can be challenging due to the large core radiation (and resulting low core temperature) that can be faced with this heavy metallic impurity if its relative concentration is too high. Nitrogen injection during the plasma current ramp-up of WEST discharges greatly improves core temperature and Magneto-Hydro-Dynamic stability. Experimental measurements and integrated simulations with the RAPTOR code complemented with the Qualikiz Neural Network for computing turbulent transport allow a detailed understanding of the mechanisms at play. Increased edge radiation during this transient phase is shown to improve confinement properties, driving higher core temperature and better MHD stability. This also leads to increased operation margins with respect to Tungsten contamination.

Abstract 1122‐000012: Study Design and Selection Criteria of a Large Core Thrombectomy Trial —— ANGEL‐ASPECT

Introduction : The ANGEL‐ASPECT trial (NCT 04551664) is an ongoing, multicenter, randomized controlled trial (RCT) currently being conducted in China. The goal of ANGEL‐ASPECT’s is to include the maximum patients with a true large core for whom EVT is not recommended under current guidelines with level 1 evidence. By enrolling patients with ASPECTS <6, expanding the window to 24h from stroke onset (beyond the windows in DAWN and DEFUSE3), and defining large core volume as >70 cc, ANGEL‐ASPECT maximizes the inclusion of patients with true large cores. What’s more, intracranial atherosclerotic disease (ICAD) is common in the Asian population while most of the previous trials have been performed in the Western world where ICAD is less prevalent. Methods : We reviewed the merits of ANGEL‐ASPECT’s design and suggest that it be included in the discussion of patient selection criteria in large core trials. Results : The primary goal of our trial is to determine whether EVT will benefit or harm AIS patients with LVO and a “large core” infarct. The inclusion criteria for ANGEL‐ASPECT are: 1. If ASPECTS is 3–5 and presentation is within 24 hours of onset, patients are enrolled without obtaining CTP. 2. If ASPECTS is >5 and presentation is beyond 6 hours of onset, only patients with relative cerebral blood flow (rCBF) of < 30% by CTP or apparent diffusion coefficient (ADC) of < 620 on MRI and estimated core volume of 70–100 cc are enrolled. 3. If ASPECTS is <3, only patients with rCBF < 30% or ADC on MRI < 620 and estimated core volume of 70–100 cc are enrolled. Patients are enrolled under a pre‐specified protocol. Each randomized patient is qualified by two core lab members who are available at all hours to calculate ASPECTS and infarct core volume using specialized, RAPID software. Conclusions : We believe that defining core volume using CTP can compensate for the inconsistencies of ASPECTS if we exclude patients with onset within six hours and core volume of 50–70 cc since these patients have already been shown to benefit from EVT in multiple RCTs. We believe that this decision captures more patients with true large core volumes for the trial. The ANGEL‐ASPECT inclusion criteria also eliminate the second group of “good ASPECTS + unfavorable CTP” . The sample size of our trial is calculated based on studies excluding these populations. The power of the trial was maintained for the relatively consistent large core volume patient population.

Seismic detection of the martian core

Clues to a planet’s geologic history are contained in its interior structure, particularly its core. We detected reflections of seismic waves from the core-mantle boundary of Mars using InSight seismic data and inverted these together with geodetic data to constrain the radius of the liquid metal core to 1830 ± 40 kilometers. The large core implies a martian mantle mineralogically similar to the terrestrial upper mantle and transition zone but differing from Earth by not having a bridgmanite-dominated lower mantle. We inferred a mean core density of 5.7 to 6.3 grams per cubic centimeter, which requires a substantial complement of light elements dissolved in the iron-nickel core. The seismic core shadow as seen from InSight’s location covers half the surface of Mars, including the majority of potentially active regions—e.g., Tharsis—possibly limiting the number of detectable marsquakes.