• Proceedings of the Korean Vacuum Society Conference
• /
• 2003.02a
• /
• pp.214-214
• /
• 2003

• The Bulletin of The Korean Astronomical Society
• /
• v.46 no.2
• /
• pp.47.2-47.2
• /
• 2021

The present study is focused on origins of the flow and magnetic structure involved in the formation and eruption of a solar prominence. To clarify them, we performed an MHD simulation based on the 3-dimensional emerging flux tube (3DEFT) model, in which self-consistent evolution of a flow and magnetic field passing freely through the solar surface was obtained by seamlessly connecting subsurface dynamics with surface dynamics. By analyzing Lagrangian displacements of magnetized plasma elements, we demonstrate the flow structure which is naturally incorporated to the magnetic structure of the prominence formed via dynamic interaction between the flow and magnetic field.

• Proceedings of the KIEE Conference
• /
• 1992.07b
• /
• pp.949-951
• /
• 1992

A low pressure DC plasma jet has been used to obtain diamond films from a mixture of $CH_4$ and $H_2$ with high deposition rate (>1$\mu\textrm{m}$/min). The effects of the deposition conditions such as torch geometry, substrate temperature, gas mixing ratio, chamber pressure, axial magnetic field on the diamond film properties such as morphology, purity, uniformity of the film and deposition rate, etc. have been examined with the aid of Scanning Electron Microscopy, X-Ray Diffraction, and Raman Spectroscopy. Both the growth rate and particle size increased rapidly for low methane concentrations but saturated and the morphology changed from octahedral to cubic structure when the concentration exceeded 1.0 %. Higher growth rates (>1.5${\mu}m$/min) can be obtained by applying an axial magnetic field to the DC plasma jet. Diamond obtained from the magnetized plasma jet also shows a sharp peak at 1332.5$cm^{-1}$ in the Raman Spectra and this result implies that higher growth rate with a good quality diamond films can he obtained by applying an external magnetic field to the plasma jet.

• Proceedings of the KIEE Conference
• /
• 1999.11d
• /
• pp.1066-1068
• /
• 1999

Magnetic field is commonly used in low temperature processing plasmas in order to obtain high density. E $\times$ B magnetron or surface multipole configuration were most popular. However, the properties of capacitively coupled rf plasma confined by axially applied static magnetic fields have rarely been studied. In this paper, the effects of magnetic field on the characteristics of 13.56MHz/40KHz argon plasma will be reported. Ion saturation current, electron temperature and plasma potential were measured by Langmuir probe and omissive probe. At low pressure region ($\sim$10mTorr), ion current was increased by a factor of 3 - 4 due to reduction of diffusion loss of charged particles to the wall. It was observed that magnetic field induces large time variation of the plasma potential. The experimental result was compared with particle-in-cell simulation. It was also observed that electron temperature tend to decrease with increasing magnetic induction level for 40KHz discharge.

• Transactions on Electrical and Electronic Materials
• /
• v.1 no.2
• /
• pp.12-17
• /
• 2000

Helicon waves were excited by a Nagoya type III antenna in magnetized plasma, and hydrogen and methane are fed through a Mass Flow Controller(MFC). We made a diagnosis of properties of helicon plasma by H$_2$gaseous discharge, and fabricated the diamond thin film. The maximum measured electron density was 1${\times}$10$\^$10/ cm$\^$-3/. Diamond films have been growo on (100) silicon substrate using the helicon plasma chemical vapor deposition. Diamond films were deposited at a pressure of 0.1 Torr, deposition time of 40~80 h, a substrate temperature of 700$^{\circ}C$ and methane concentrations of 0.5~2.5%. The growth characteristics were investigated by means of X-ray Photoelectron (XPS) and X-ray Diffraction(XRD), XRD and XPS analysis revealed that SiC was formed, and finally diamond particles were definitely deposited on it. With increasing deposition time, the thickness and crystallization of the daimond thin film increased, For this system the optimum condition of methane concentration was estimated to near to 1.5%.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.64 no.4
• /
• pp.560-566
• /
• 2015

The self-consistent simulation based on the drift-diffusion approximation with anisotropic transport coefficients was performed. The RHCP-wave propagation was observed in MICP and this wave was refracted toward the high-density region. The calculated impedance seen from the antenna terminal shows that resistance component of MICP is a higher than that of ordinary ICP. Because of a higher resistance, the power transfer efficiency was improved to 95%. This property is practically important for large-size, low-pressure plasma sources because high resistance corresponds to high power-transfer efficiency and stable impedance matching characteristics.

• Journal of electromagnetic engineering and science
• /
• v.18 no.3
• /
• pp.212-214
• /
• 2018

The finite-difference time-domain (FDTD) model was developed to analyze electromagnetic (EM) wave propagation in an inhomogeneous ionosphere. The EM analysis of ionosphere is complicated, owing to various propagation environments that are significantly influenced by plasma frequency, cyclotron frequency, and collision frequency. Based on the simple auxiliary differential equation (ADE) technique, we present an accurate FDTD algorithm suitable for the EM analysis of complex phenomena in the ionosphere under arbitrary-direction geomagnetic field. Numerical examples are used to validate our FDTD model in terms of the reflection coefficient of a single magnetized plasma slab. Based on the FDTD formulation developed here, we investigate EM wave propagation characteristics in the ionosphere using realistic ionospheric data for South Korea.

• Proceedings of the KIEE Conference
• /
• 1993.11a
• /
• pp.261-263
• /
• 1993

The effects of the magnetic field and gas pressure on the etching characteristics were investigated in the axial magnetic field enhanced RIE system. This system has many advantages compared with the conventional RIE system ; the capability of operating at low pressure, low self-bias voltage, high electron density and high etch rate in the low pressure, but also has disadvantages such as the nonconformity of plasma density which intensifies as the magnitude of magnetic field increases. To overcome this problem we made some grooved anode and tried to find the optimal pressure and B-field strength.

• Proceedings of the IEEK Conference
• /
• 2001.06b
• /
• pp.37-40
• /
• 2001

The semiconductor's design rule becomes more stringent, hence the silicon-dioxide etching technique is important issue. In this work we compared the etching characteristics of different three types of Plasma source, Normal ICP, magnetized ICP and E-IC $P^{TM}$. The E-IC $P^{TM}$ source shows higher etch rate at lower pressure and this is advantageous for the fine pattern process. The etching characteristics were varied with external magnetic field frequency at I-lCP and this is examined with Nanospe $c^{TM}$ and SEM. We designed Langmuir probe system for time resolved diagnosis. ion density of E-ICP is varying periodically with the applied external magnetic field frequencyquency

• The Bulletin of The Korean Astronomical Society
• /
• v.40 no.1
• /
• pp.49.2-49.2
• /
• 2015

IntraCluster Medium (ICM) located at the galaxy cluster is in the state of very hot, tenuous, magnetized, and highly ionized X-ray emitting plasmas. High temperature and low density make ICM very viscous and conductive. In addition to the high conductivity, fluctuating random plasma motions in ICM, occurring at all evolution stages, generate and amplify the magnetic fields in such viscous ionized gas. The amplified magnetic fields in reverse drive and constrain the plasma motions beyond the viscous scale through the magnetic tension. Moreover, without the influence of resistivity viscous damping effect gets balanced only with the magnetic tension in the extended viscous scale leading to peculiar ICM energy spectra. This overall collisionless magnetohydrodynamic (MHD) turbulence in ICM was simulated using a hyper diffusivity method. The results show the plasma motions and frozen magnetic fields have power law of $E_V^k{\sim}k^{-3}$, $E_M^k{\sim}k^{-1}$. To explain these abnormal power spectra we set up two simultaneous differential equations for the kinetic and magnetic energy using an Eddy Damped Quasi Normal Markovianized (EDQNM) approximation. The solutions and dimensions of leading terms in the coupled equations derive the power spectra and tell us how the spectra are formed. We also derived the same results with a more intuitive balance relation and stationary energy transport rate.