نتایج جستجو برای: مگنتوهیدرودینامیک mhd

تعداد نتایج: 9709  

ژورنال: فیزیک زمین و فضا 2010
براتعلی فیض آبادی محمود میرزایی ناصر حسین‌زاده گویا

یک شبیه‌سازی عددی بزرگ‌مقیاس بر‌اساس نظری? مگنتوهیدرودینامیک طراحی شد تا سیر تکاملی تأثیر شرایط فیزیکی بر مغناطیس‌سپهر را بر‌اساس اندازه‌گیری پارامترهای باد خورشیدی تشریح ‌کند. با توجه به وسعت زیاد مغناطیس‌سپهر و وابستگی زیاد فضایی فرآیند انتقال انرژی، مقدار انرژی انتقالی نمی‌تواند مستقیماً روی سطح مغناطیس‌سپهر، مگنتوپاوز نامیده می‌شود، اندازه‌گیری شود. بنابراین انجام شبیه‌سازی می‌تواند امکان مح...

2007
Yu-Qing Lou

In broad astrophysical contexts of large-scale gravitational collapses and outflows and as a basis for various further astrophysical applications, we formulate and investigate a theoretical problem of self-similar magnetohydrodynamics (MHD) for a non-rotating polytropic gas of quasi-spherical symmetry permeated by a completely random magnetic field. Within this framework, we derive two coupled ...

2015
Yue Ji Xing-fei Li Tengfei Wu Cheng Chen

The magnetohydrodynamics angular rate sensor (MHD ARS) has received much attention for its ultra-low noise in ultra-broad bandwidth and its impact resistance in harsh environments; however, its poor performance at low frequency hinders its work in long time duration. The paper presents a modified MHD ARS combining Coriolis with MHD effect to extend the measurement scope throughout the whole ban...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه کاشان - دانشکده مهندسی 1389

چکیده در این تحقیق جریان توسعه یافته آرام سیال هادی جریان الکتریسیته در یک میکروپمپ مغناطیسی در حالت گذرا بصورت عددی مطالعه شده است. در ابتدا هیدرودینامیک مغناطیسی معرفی شده و سپس اثر نیروی لورنتز نوسانی در میکروپمپ مگنتوهیدرودینامیک بررسی شده است. سپس معادلات مربوط به سرعت و دما در جریان آرام توسعه یافته گذرا در حضور میدان الکتریکی و مغناطیسی اعمالی به همراه شرایط مرزی مناسب برای هندسه مورد ن...

2005
H. Safari Y. Sobouti

We study the resonant absorption of MHD waves in magnetized flux tubes with a radial density inhomogeneity. Within the approximation that resistive and viscous processes are operative in thin layers surrounding the singularities of the MHD equations, we give the full spectrum of the eigenfrequencies and damping rates of the MHD quasi modes of the tube. Both surface and body modes are analyzed.

2000
K. KABIN

Magnetohydrodynamics (MHD) provides an approximate description of a great variety of processes in space physics. Accurate numerical solutions of the MHD equations are still a challenge, but in the past decade a number of robust methods have appeared. Once these techniques made the direct solution of MHD equations feasible, a number of global three-dimensional models were designed and applied to...

2005
R. Lundin M. Yamauchi

The notion of frozen-in magnetic field originates from H. Alfvén, the result of a work on electromagnetichydrodynamic waves published in 1942. After that, the notion of frozen-in magnetic field, or ideal MHD, has become widely used in space plasma physics. The controversy on the applicability of ideal MHD started in the late 1950s and has continued ever since. The applicability of ideal MHD is ...

Journal: :journal of nanostructures 2015
m. merikhi g. nabiyouni b. ghanbari

in this paper, the effect of magnetic field on the morphology, structure and magnetic properties of electrodeposited fecu/cu thin films was investigated. the films were deposited on au2pdag/glass substrates using electrodeposition technique in potentiostatic control. the magnetic fields of 5000 and 7000 oe were applied on deposition bath during deposition. two series of thin films were prepared...

1998
Abhik Basu Anirban Sain Sujan K. Dhar Rahul Pandit

From a numerical study of the magnetohydrodynamic (MHD) equations we show, for the first time in three dimensions sd ­ 3d, that velocity and magnetic-field structure functions exhibit multiscaling, extended self-similarity (ESS), and generalized extended self-similarity (GESS). We propose a new shell model for homogeneous and isotropic MHD turbulence, which preserves all the invariants of ideal...

2003
Fabien CASSE

In this proceeding I present recent works dealing with MHD simulations describing resistive accretion disks continuously launching large-scale, self-collimated MHD jets. In particular, I discuss the physical conditions required to produce these outflows and the related numerical issues. As an illustration I also present axisymmetric MHD numerical simulations of such accretion-ejection engines, ...

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