Magnetized Fast Isochoric Laser Heating for Efficient Creation of Ultra-High-Energy-Density States

The quest for the inertial confinement fusion (ICF) ignition is a grand challenge, as exemplified by extraordinary large laser facilities. Fast isochoric heating of a pre-compressed plasma core with a high-intensity short-pulse laser is an attractive and alternative approach to create ultra-high-energy-density states like those found in ICF ignition sparks. This avoids the ignition quench caused by the hot spark mixing with the surrounding cold fuel, which is the crucial problem of the currently pursued ignition scheme. High-intensity lasers efficiently produce relativistic electron beams (REB). A part of the REB kinetic energy is deposited in the core, and then the heated region becomes the hot spark to trigger the ignition. However, only a small portion of the REB collides with the core because of its large divergence. Here we have demonstrated enhanced laser-to-core energy coupling with the magnetized fast isochoric heating. The method employs a kilo-tesla-level magnetic field that is applied to the transport region from the REB generation point to the core which results in guiding the REB along the magnetic field lines to the core. 7.7 $\pm$ 1.3 % of the maximum coupling was achieved even with a relatively small radial area density core ($\rho R$ $\sim$ 0.1 g/cm$^2$). The guided REB transport was clearly visualized in a pre-compressed core by using Cu-$K_\alpha$ imaging technique. A simplified model coupled with the comprehensive diagnostics yields 6.2\% of the coupling that agrees fairly with the measured coupling. This model also reveals that an ignition-scale areal density core ($\rho R$ $\sim$ 0.4 g/cm$^2$) leads to much higher laser-to-core coupling ($>$ 15%), this is much higher than that achieved by the current scheme

Hot electron and ion spectra on blow-off plasma free target in GXII-LFEX direct fast ignition experiment

Polystyrene deuteride shell targets with two holes were imploded by the Gekko XII laser and additionally heated by the LFEX laser in a direct fast ignition experiment. In general, when an ultra-intense laser is injected into a blow-off plasma created by the imploding laser, electrons are generated far from the target core and the energies of electrons increase because the electron acceleration distance has been extended. The blow-off plasma moves not only to the vertical direction but to the lateral direction against the target surface. In a shell target with holes, a lower effective electron temperature can be realized by reducing the inflow of the implosion plasma onto the LFEX path, and high coupling efficiency can be expected. The energies of hot electrons and ions absorbed into the target core were calculated from the energy spectra using three electron energy spectrometers and a neutron time-of-flight measurement system, Mandala. The ions have a large contribution of 74% (electron heating of 4.9 J and ion heating of 14.1 J) to target heating in direct fast ignition

Combination of shear-wave elastography and liver fibrosis markers predicts severe fibrosis in patients with non-alcoholic steatohepatitis

　非アルコール性脂肪性肝疾患（Non-alcoholic fatty liver disease：NAFLD）の中から予後の悪い線維化が進展した非アルコール性脂肪肝炎（Non-alcoholic steatohepatitis：NASH）を非侵襲的診断法にて拾い上げることが重要である．今回，バイオマーカーやshear wave elastography（以下 SWE）を組み合わせた非侵襲的診断における肝線維化進展症例の診断能の向上について検討を行った．肝生検および SWE を施行し，肝線維化マーカーを測定した NAFLD 患者140名を対象とし，SWE 値と肝線維化マーカーの測定を行い線維化進展例（stage3以上）の診断の拾い上げについて検討した．各種線維化マーカーは stage3-4の線維化進展例で有意に上昇を認め，SWE においてはstage2の段階から上昇し，他の線維化マーカーより早い段階から NASH の線維化の診断ができた．SWE，Ⅳ型コラーゲン7S，WFA+M2BP，P-Ⅲ-P，ヒアルロン酸，FIB4 index における stage3以上の AUC はそれぞれ0.86，0.83，0.79，0.75，0.75，0.77であった．さらに SWE と線維化マーカーを組み合わせたところ，AUC はそれぞれ0.92，0.88，0.86，0.88，0.88で診断能の上昇を認めた．特に SWE とⅣ型コラーゲン7S の診断能が最も優れていた．NASH における SWE は簡便に線維化進展の診断が可能であり，バイオマーカーを組み合わせることで肝線維化診断能が上昇した．以上より線維化の軽度な NASH 症例や非アルコール性脂肪肝（Non-alcoholic fatty liver：NAFL）を識別し，肝生検を減少させる可能性があり，NAFLD の予後の改善に繋がると思われた．　In the recent years, the incidence of nonalcoholic fatty liver disease (NAFLD) is increasing rapidly worldwide. It is important to detect nonalcoholic steatohepatitis (NASH) with a poor prognosis in patients with NAFLD using noninvasive diagnostic methods. Conventional ultrasound (US) is the most common, low-cost technique for NASH diagnosis and improving patient prognosis. We studied the usefulness of US elastography (shear-wave elastography [SWE]) in diagnosing liver fibrosis (LF) with NAFLD and examined the possibility of improving the diagnosis of patients with advanced LF by combining SWE and LF-marker testing. The subjects were 140 patients with NAFLD who underwent liver biopsies, SWE, and LF-marker tests, such as type IV collagen 7S, Wisteria floribunda agglutinin-positive Mac-2 binding protein (WFA[+]-M2BP), P-Ⅲ-P, hyaluronic acid, and fibrosis-4 (FIB4) index, at the General Medical Center, Kawasaki Medical School. We evaluated the efficacy of combined SWE and LF-marker tests to diagnose advanced LF (stage ≥3). SWE was performed using 3.75-MHz probes (Canon Aplio 500, JAPAN). There were minimal differences in LF-marker levels for NASH stages 0–2, whereas significantly increased LF-marker levels were observed in patients with advanced LF (stages 3 and 4). SWE showed significantly elevated LF-marker levels at stage 2 compared with stages 0–1, and NASH was detected earlier than other LF markers. The areas under the receiver-operating characteristic curves (AUCs) for SWE, type IV collagen 7S, WFA(+)-M2BP, P-Ⅲ-P, hyaluronic acid, and FIB4 index for stage ≥3 were 0.86, 0.83, 0.79, 0.75, 0.75, and 0.77, respectively. With combined SWE and LF markers, the AUCs increased to 0.92, 0.88, 0.86, 0.88, and 0.88, respectively, showing increased diagnostic ability compared to that of single markers. The diagnostic ability of combined SWE and type IV collagen 7S was superior to that of other combinations. In addition, we detected that most cases were in stage ≥3 on combining SWE and LF markers. SWE for NASH can simply diagnose LF progression; the diagnostic capacity of SWE for LF improves in combination with LF-marker tests. It may be possible to detect the need for liver biopsy and treatment or follow-up, as well as reduce the number of liver biopsies by identifying NAFLD with low LF levels