A mass-energy-conserving discontinuous Galerkin scheme for the isotropic multispecies Rosenbluth--Fokker--Planck equation

Structure-preserving discretization of the Rosenbluth-Fokker-Planck equation is still an open question especially for unlike-particle collision. In this paper, a mass-energy-conserving isotropic Rosenbluth-Fokker-Planck scheme is introduced. The structure related to the energy conservation is skew-symmetry in mathematical sense, and the action-reaction law in physical sense. A thermal relaxation term is obtained by using integration-by-parts on a volume integral of the energy moment equation, so the discontinuous Galerkin method is selected to preserve the skew-symmetry. The discontinuous Galerkin method enables ones to introduce the nonlinear upwind flux without violating the conservation laws. Some experiments show that the conservative scheme maintains the mass-energy-conservation only with round-off errors, and analytic equilibria are reproduced only with truncation errors of its formal accuracy

Non-ideal Ballooning Mode Instability with Real Electron Inertia

Impacts of electron inertia with an electron skin depth (ESD) longer than the realistic value used in early numerical studies on non-ideal ballooning modes (NIBMs) are numerically investigated by a linearized 3-field reduced MHD model. In this paper, 4 different ESDs,are used for an resistivity dependence study of the growth rate of NIBMs, where de s the real ESD and d*e = 10 corresponds to an order of ESD used in a numerical study on collisionless ballooning mode (CBM) reported in [Kleva and Guzdar Phys. Plasmas 6, 116 (1999)]. In the case with the real ESD d*e = de, a transition from resistive ballooning mode (RBM) to CBM occurs in the edge relevant resistivity regime, while the electron inertia effect is overestimated and the growth rate is almost independent of resistivity in the cases with d∗e =√10de and 10de. These results indicate that the real ESD is one of key factors for the edge stability and turbulence analysis

Shaping Effects on Non-ideal Ballooning Mode

The dependence of shaping effects on the growth rate of collisionless and resistive ballooning mode (CBM/RBM) is numerically investigated. That of the drift ballooning modes (DCBM/DRBM) is also investigated by taking kinetic effects into account. Resistivity scans of linear growth rates of CBM/RBM and DCBM/DRBM in a circular geometry show that both modes have 3 branches in accordance with decreasing resistivity, fast, re- sistive and collisionless branch. The last two branches are in the edge relevant resistivity regime and are in the scope of this paper. For CBM/RBM, shaping effect on the growth rate becomes weak with increasing resistivity and the growth rate monotonically increases with decrease of the elongation and increase of the triangularity, on the other hand, the opposite tendency appears on the triangularity for DCBM, namely it weakly decreases with increase of the triangularity. This fact indicates that the inverted D-shaped equilibrium can be unstable against DCBM compared with the D-shaped equilibrium

Experimental study of non-inductive current in Heliotron J

It is important to control non-inductive current for generation and steady-state operation of highperformance plasmas in toroidal fusion devices. Helical devices allow dynamic control of non-inductivecurrent through a wide variety of magnetic configurations. The reversal of non-inductive current consisting of bootstrap current and electron cyclotron driven current in electron cyclotron heating plasmas has been observed in a specific configuration at low density in Heliotron J device. By analyzing thenon-inductive current for normal and reversed magnetic fields, we present experimental evidence for the reversal of bootstrap current. Our experiments and calculations suggest that the reversal is caused bya positive radial electric field of about 10 kV/m. Moreover, we show that the typical electron cyclotron current drive efficiency in Heliotron J plasma is about 1.0 × 1017 AW?1m?2, which is comparable to other helical devices. We have found that the value is about 10 times lower than that of tokamak devices. This might be due to an enhanced Ohkawa effect by trapped particles

Insufficiency of phosphatidylethanolamine N-methyltransferase is risk for lean non-alcoholic steatohepatitis

　Although obesity is undoubtedly major risk for non-alcoholic steatohepatitis (NASH), the presence of lean NASH patients with normal body mass index has been recognized. Here, we report that the insufficiency of phosphatidylethanolamine N-methyltransferase (PEMT) is a risk for the lean NASH. The Pemt−/− mice fed high fat-high sucrose (HFHS) diet were protected from diet-induced obesity and diabetes, while they demonstrated prominent steatohepatitis and developed multiple liver tumors. Pemt exerted inhibitory effects on p53-driven transcription by forming the complex with clathrin heavy chain and p53, and Pemt−/− mice fed HFHS diet demonstrated prominent apoptosis of hepatocytes. Furthermore, hypermethylation and suppressed mRNA expression of F-box protein 31 and hepatocyte nuclear factor 4α resulted in the prominent activation of cyclin D1. PEMT mRNA expression in liver tissues of NASH patients was significantly lower than those with simple steatosis and we postulated the distinct clinical entity of lean NASH with insufficiency of PEMT activities

非軸対称トロイダルプラズマにおける新古典輸送行列のモンテカルロ計算に関する研究

京都大学0048新制・課程博士博士(エネルギー科学)甲第15494号エネ博第215号新制||エネ||47(附属図書館)27972京都大学大学院エネルギー科学研究科エネルギー基礎科学専攻(主査)准教授 花谷 清, 教授 佐野 史道, 教授 岸本 泰明学位規則第4条第1項該当Doctor of Energy ScienceKyoto UniversityDA