Optical emission spectroscopy (OES) is a common method for characterizing radio frequency (RF) discharge plasmas. Particulary, helicon plasma is featured by its high plasma density among all RF-excited plasmas. In order to obtain the spatial-resolved information of a helicon plasma, local optical emission spectroscopy (LOES) with a 3 mm spatial resolution was proposed and carried out to evaluate the local electron density and temperature. The plasma emission intensity via LOES was measured and compared with the electron density obtained by a RF-compensated Langmuir probe (LP) in Ar, N 2 and Air helicon plasmas, respectively. The results revealed that there existed a functional relationship between some specific lines (LOES) and electron density (LP). Further, helicon plasma characteristics under capacitive (E) , inductive (H), and helicon (W) modes were systemetically investigated based on LOES. Besides, two-dimensional (2D) contour maps for plasma distributions were made via LOES as well. It was found that in E-and H-modes, axial profiles of plasma density and electron temperature were consistent under two opposite magnetic field directions. However, in W-mode, the plasma presented an asymmetric axial profile along the tube. As for radial profiles, plasma distribution varied under three discharge modes due to different heating mechanisms in Ar, N 2 or Air helicon plasma. A deeper analysis indicated that the bulk absorption comes from the coupling of the helicon wave in Ar helicon plasma while the power depositions in N 2 and Air helicon plasma are mainly dominated by the TG wave.
In this paper, two types of stationary striations appearing in an argon helicon plasma source are presented. The formation and features of the striations were investigated experimentally under different conditions, including RF power, gas pressure, and external magnetic field. The results show that the striation spacing decreases as the gas pressure increases but does not change significantly along with the magnetic field and the RF power. It is suggested that these striations are strongly related to the non-local effect of electron kinetics in the plasma channel with a weak electric field. The different pressures in downstream and antenna regions will lead to different types of striations in an argon helicon plasma source.
This paper focus on the problem of high side lobes, which will appear near the site of grating lobes in the array factor when enlarging the interval between elements to solve the effect of mutual coupling. It is difficult to meet the requirement of making up antenna array and scanning. In this paper, taking plate end-fire antenna as the array elements arranged along the lateral, axial and two-dimensional directions, CST simulation results and DBF method of virtual element interpolation calculation results of the far field pattern were compared and analyzed. Then, the effectiveness of the DBF method of virtual element interpolation in suppressing the side lobe level was proved. Finally, based on the same computational complexity, non-uniform interpolation was proposed to obtain better far field pattern.
Based on complex ray tracing ( C l W ) unci pnraxial approx i m a t i o n (CHPA),the wave f i u l d s of u (;*auucian-like beam covered by a n u r b i t r u r i l y c u r v e d rildorne a r e a n t i l y x o d . Formulas and numerical r e s u l t s shaw thilt C1IPA i G ti Usef u l method for f i e l d c a l c u l a t i o n u n d e r c o m p l i c t l t u d environments. THEORETICAL ANALYSIS The s u r f a c e o f a s i n g l e -l a y e r e d 2-D a r b i t r a r i l y c u r v e d radome may be d e s c r i b e d by t h e f u n c t i o n Fi(X,Y)=O, x i 1 s X s X i 2 (i=1,2)r ( 1 ) A z -p o l a r i z e d beam s o u r c e a n d o b G e r v a t i o n p o i n t s are l o c a t e d a t S(xs,ys) a n d P(x,y),respectively,inside and o u t s i d e t h e r a d o m e ( F i g . 1 1. A c c o r d i n g t o c o m p l e x r a y t h e o r y , t h e beam s o u r c e may be c o n s i d e r e d as a complex source point und the wave f i e l d a t t h e obtierver P , t a k i n g m u l t i p l y i r l t e r n a l r e f l e c t i o n i n t o a c c o u n t , 1 s g i v e n by C R T~ 1 Iv uq01 M=O u= z uw . w ( 2 ) where Fy r e p r e s e n t s the i n d i v i d u a l cornplex r a y f i e l d h with M d e n o t i n g t h e number of i n t e r n a l r e f l e c t i o n a n d 'PM,cM and yM d e n o t i n g t h e t o t a l r e f l e c t i o n -t r a n s m i s s i o n h
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.