Variation Of Electron Temperature Research Articles

Long-term variations in peak electron density and temperature of mesopause region: Dependence on solar, geomagnetic, and atmospheric activities, long-term trends

The paper overviews the main results of the study of long-term variations in characteristics of the upper neutral atmosphere and ionosphere, obtained during the implementation of Russian Science Foundation Project No. 22-17-00146 “Experimental and theoretical study of the coupling neutral and ionized components of Earth’s atmosphere”. We study and compare long-term variations in the peak electron density and temperature of the mesopause region. Their dependences on solar, geomagnetic, and atmospheric activity, as well as long-term trends, are analyzed. The analysis is based on data from long-term measurements with the ISTP SB RAS complex of instruments. The peak electron density (NmF2) data was acquired with the Irkutsk analog automatic ionospheric station for 1955–1996 and the Irkutsk digital ionosonde DPS-4 for 2003–2021. The atmospheric temperatures at mesopause altitudes (Tm) were obtained from spectrometric observations of the hydroxyl molecule emission (OH (6-2) band, 834.0 nm, emission maximum height ~87 km) for 2008–2020. The analysis uses solar (F10.7) and geomagnetic (Ap) activity indices, as well as data on variations in the Southern Oscillation Index (SOI). The study employs simple and multiple linear regression methods. Annual average NmF2 values are found to be predominantly controlled by changes in solar flux. Analysis of regression residuals shows that the largest deviations from regression (for both simple and multiple regression) are observed in years near the maxima of solar cycles 19 (1956–1959) and 22 (1989–1991). Annual average temperature variability in the mesopause region correlates with changes in the SOI index: day-to-day variability exhibits a positive correlation with SOI; and intra-diurnal variability, a negative correlation with SOI. No significant relationship was found between year-to-year variations in the NmF2 and Tm variability.

Долговременные вариации максимума электронной концентрации и температуры области мезопаузы: зависимости от солнечной, геомагнитной и атмосферной активности, долговременные тренды

The paper overviews the main results of the study of long-term variations in characteristics of the upper neutral atmosphere and ionosphere, obtained during the implementation of Russian Science Foundation Project No. 22-17-00146 “Experimental and theoretical study of the coupling neutral and ionized components of Earth’s atmosphere”. We study and compare long-term variations in the peak electron density and temperature of the mesopause region. Their dependences on solar, geomagnetic, and atmospheric activity, as well as long-term trends, are analyzed. The analysis is based on data from long-term measurements with the ISTP SB RAS complex of instruments. The peak electron density (NmF2) data was acquired with the Irkutsk analog automatic ionospheric station for 1955–1996 and the Irkutsk digital ionosonde DPS-4 for 2003–2021. The atmospheric temperatures at mesopause altitudes (Tm) were obtained from spectrometric observations of the hydroxyl molecule emission (OH (6-2) band, 834.0 nm, emission maximum height ~87 km) for 2008–2020. The analysis uses solar (F10.7) and geomagnetic (Ap) activity indices, as well as data on variations in the Southern Oscillation Index (SOI). The study employs simple and multiple linear regression methods. Annual average NmF2 values are found to be predominantly controlled by changes in solar flux. Analysis of regression residuals shows that the largest deviations from regression (for both simple and multiple regression) are observed in years near the maxima of solar cycles 19 (1956–1959) and 22 (1989–1991). Annual average temperature variability in the mesopause region correlates with changes in the SOI index: day-to-day variability exhibits a positive correlation with SOI; and intra-diurnal variability, a negative correlation with SOI. No significant relationship was found between year-to-year variations in the NmF2 and Tm variability.

MUSE spectroscopy of the high abundance discrepancy planetary nebula NGC\,6153

The abundance discrepancy problem in planetary nebulae (PNe) has long puzzled astronomers. NGC\,6153, with its high abundance discrepancy factor (ADF sim 10), provides a unique opportunity to study the chemical structure and ionisation processes within these objects. We aim to understand the chemical structure and ionisation processes in this high-ADF nebula by constructing detailed emission line maps and examining variations in electron temperature and density. This study also explores the discrepancies between ionic abundances derived from collisional and recombination lines, shedding light on the presence of multiple plasma components. We used the MUSE spectrograph to acquire IFU data covering the wavelength range 4600$-$9300 with a spatial sampling of 0.2 arcsec and spectral resolutions ranging from R = 1609 to R = 3506. We created emission line maps for 60 lines and two continuum regions. We developed a tailored methodology for the analysis of the data, including correction for recombination contributions to auroral lines and the contributions of different plasma phases. Our analysis confirmed the presence of a low-temperature plasma component in NGC\,6153. We find that electron temperatures derived from recombination line and continuum diagnostics are significantly lower than those derived from collisionally excited line diagnostics. Ionic chemical abundance maps were constructed, considering the weight of the cold plasma phase in the emission. Adopting this approach we found ionic abundances that could be up to 0.2 dex lower for those derived from CELs and up to 1.1 dex higher for those derived from RLs than in the case of a homogeneous emission. The abundance contrast factor (ACF) between both plasma components was defined, with values, on average, 0.9 dex higher than the ADF. Different methods for calculating ionisation correction factors (ICFs), including state-of-the-art literature ICFs and machine learning techniques, yielded consistent results. Our findings emphasise that accurate chemical abundance determinations in high-ADF PNe must account for multiple plasma phases. Future research should focus on expanding this methodology to a broader sample of PNe, with spectra deep enough to gather physical condition information of both plasma components, which will enhance our understanding of their chemical compositions and the underlying physical processes in these complex objects.

Electron-scale turbulence characteristics with varying electron temperature gradient in LHD

Electron-scale turbulence, whose wavelength is the electron Larmor radius, is thought to have the potential to cause stiffness in an electron temperature gradient and degrade the confinement of future burning plasma in which the electron heating by alpha particles is dominant. The dependence of electron-scale turbulence and electron heat flux on the electron temperature inverse gradient length Rax/LTe , were investigated. The electron temperature gradient was successfully varied in the range of −3<Rax/LTe<12 by controlling the injection power of on/off-axis electron cyclotron heating. The results show a significant increase in the electron-scale turbulence with increasing Rax/LTe , especially in conditions where Electron Temperature Gradient (ETG) instability is linearly unstable, suggesting the presence of ETG turbulence at high Rax/LTe . The electron heat flux also increases steeply with increasing Rax/LTe . In addition, the electron-scale turbulence is observed even at Rax/LTe∼0 , which is stable in linear GKV calculations. Finding the cause of this phenomenon is an interesting task for the future.

Analyses of data from the first Chinese seismo electromagnetic satellite (CSES-01) together with other earthquake precursors associated with the Turkey earthquakes (February 6, 2023)

Abstract On 6 February 2023, at 01:17:35 and 10:24:49 UTC (LT = UTC + 03:00) two earthquakes with magnitude 7.8 (37.166° N, 37.042° E, depth ∼ 17.9 km) and 7.5 (38.024° N, 37.203° E, depth ∼ 10 km), respectively, heavily struck southern and central Turkey and northern and western Syria. The purpose of this study is to investigate the relation between pre-earthquake anomalies observed in different layers of the earth system and explore the earthquake mechanism of LAIC (Lithospheric Atmospheric Ionospheric Coupling) associated with earthquake precursors. To achieve this goal, electron density and temperature variations obtained from CSES-01 data in the Dobrovolsky’s area the Turkey earthquakes are analyzed in the period from November 1, 2022 to February 10, 2023. Since investigating the LAIC mechanism requires multi-precursor analysis, anomalies obtained from CSES-01 data were compared with the behavior of anomalies obtained from other lithospheric, atmospheric and ionospheric precursors in the same location and time of the study area. These anomalies that were analyzed in the previous study are: (1) TEC data obtained from GPS-GIM maps, (2) electron density and temperature variations obtained from Swarm satellites (Alpha, Bravo and Charlie) measurements, (3) Atmospheric data including water vapour, methane, ozone, CO and AOD obtained from the measurements of OMI and AIRS satellites, and (4) Lithospheric data including number of earthquakes obtained from USGS and also surface temperature obtained from the measurements of AIRS satellite. It should be noted that clear anomalies are observed between 1 and 5 days before the earthquake in electron density and temperature variations measured by CSES-01 during the day and night and they are in good agreement with the variations in the Swarm satellites data and GPS-TEC. The interesting and significant finding is that lithospheric anomalies are detected in the land surface temperature data in the time interval of 19–12 days before the earthquake, and then most of the atmospheric anomalies are observed in the time period of 10–5 days prior to the earthquake and at the end striking ionospheric anomalies are revealed during 5–1 days preceding the earthquake. Therefore, the results of this study confirm the sequence of appearing of earthquake precursors from the lower layers of the lithosphere to the upper layers of the ionosphere during 1–15 days before the earthquake, and finally proving the LAIC mechanism can significantly contribute to the efficiency and lower uncertainty of earthquake early warning systems in the future.

Evaluating plasma fluctuation by collisional-radiative model using Malliavin derivative

Abstract Non-equilibrium plasma has garnered significant attention due to its involvement in short-term phenomena. One example is plasma fluctuation, encompassing variations in electron temperature or density. This phenomenon is explored not only in nuclear fusion but also in semiconductor etching and thin film deposition. This study introduces an evaluation method employing Malliavin derivatives to predict plasma fluctuations based on a collisional-radiative model. This model delineates the chemical kinetics of excited states within the plasma. Given that electron impact excitation and atomic collisional processes are stochastic, they exhibit characteristics similar to a Wiener process. Furthermore, the properties of fractional Brownian motion are applied to the Malliavin derivative. The revised Wiener process is utilized to analyze the changes in excited-level populations within short durations. This approach assesses electron or atomic density fluctuations by considering the contributions of electron collisions and those of ground-state atoms.

Investigating the Drivers of Electron Temperature Variations in H ii Regions with Keck-KCWI and VLT-MUSE

H ii region electron temperatures are a critical ingredient in metallicity determinations, and recent observations have revealed systematic variations in the temperatures measured using different ions. We present electron temperatures (T e ) measured using the optical auroral lines ([N ii]λ5756, [O ii]λ λ7320, 7330, [S ii]λ λ4069, 4076, [O iii]λ4363, and [S iii]λ6312) for a sample of H ii regions in seven nearby galaxies. We use observations from the Physics at High Angular resolution in Nearby Galaxies survey (PHANGS) obtained with integral field spectrographs on Keck (Keck Cosmic Web Imager) and the Very Large Telescope (Multi-Unit Spectroscopic Explorer). We compare the different T e measurements with H ii region and ISM environmental properties such as electron density, ionization parameter, molecular gas velocity dispersion, and stellar association/cluster mass and age obtained from PHANGS. We find that the temperatures from [O ii] and [S ii] are likely overestimated due to the presence of electron density inhomogeneities in H ii regions. We measure high [O iii] temperatures in a subset of regions with high molecular gas velocity dispersion and low ionization parameter, which may be explained by the presence of low-velocity shocks. In agreement with previous studies, the T e–T e between [N ii] and [S iii] temperatures have the lowest observed scatter and follow predictions from photoionization modeling, which suggests that these tracers reflect H ii region temperatures across the various ionization zones better than [O ii], [S ii], and [O iii].

Mid- and High-Latitude Electron Temperature Dependence on Solar Activity in the Topside Ionosphere through the Swarm B Satellite Observations and the International Reference Ionosphere Model

This study focuses on the open question of the electron temperature (Te) variation with solar activity in the topside ionosphere at mid- and high latitudes. It takes advantage of in situ observations taken over a decade (2014–2023) from Langmuir probes on board the low-Earth-orbit Swarm B satellite and spanning an altitude range of 500–530 km. The study also includes a comparison with Te values modeled using the International Reference Ionosphere (IRI) model and with Millstone Hill (42.6° N. 71.5° W) incoherent scatter radar observations. The largest Te variation with solar activity was found at high latitudes in the winter season, where Te shows a marked decreasing trend with solar activity in the polar cusp and auroral regions and, more importantly, at sub-auroral latitudes in the nightside sector. Differently, in the summer season, Te increases with solar activity in the polar cusp and auroral regions, while for equinoxes, variations are smaller and less clear. Mid-latitudes generally show negligible Te variations with solar activity, which are mostly within the natural dispersion of Te observations. The comparison between measured and modeled values highlighted that future implementations of the IRI model would benefit from an improved description of the Te dependence on solar activity, especially at high latitudes.

Portable Thomson scattering system for temporally resolved plasma measurements under low density conditions.

We present the development of a portable Thomson scattering diagnostic system allowing simultaneous spatially and temporally resolved plasma property measurements for low density plasmas. The setup uses a compact pulsed Nd:YAG laser (532nm) as the light source with suppression by two volume Bragg grating notch filters and dispersion with a single-stage spectrometer before measurement with an intensified camera. A key issue is the detailed light collection and how it impacts the sensitivity and elastic light suppression, for which we have investigated two optical configurations, one based on a 7 × 1 linear fiber bundle and the other based on a slit spatial-filter. We find that the configuration with the slit spatial-filter provides a higher sensitivity by a factor of ∼2 along with more uniform spatial response. We have developed a custom pulsed-plasma setup with a modulation at 20kHz, representative of the Hall thruster breathing mode oscillation, to show the possibility of temporally resolved measurements for electric propulsion applications. We have successfully recorded the variations in electron number density and temperature with sub-mm spatial resolution and capturing ten temporal points over the 50 µs modulation period. The detection limit of electron density (with the spatial-filter configuration) is ∼1.6 × 1017m-3, which is ∼1/10 of the plasma density in the acceleration channel of Hall thrusters.

Formation and modulation of multi-pulse femtosecond laser-induced periodic surface structures by electromagnetic and partial differential equation simulations.

In order to demonstrate the formation of laser-induced periodic surface structures (LIPSS), simulations were performed to investigate the effect of multiple femtosecond laser pulses with different laser energy densities on a Ti6Al4V surface. In this work, a set of partial differential equations calculating the electron and lattice temperature variations, followed by coupling with an electric field, is used to analyze the evolution of the periodic surface structure induced by the interaction of the femtosecond laser with the material. As the number of pulses increases, the surface structure of the material changes from none to produce LIPSS structure and from low spatial frequency LIPSS (LSFL) structure to high spatial frequency LIPSS (HSFL) structure. In order to compare the results, single-point laser scanning ablation experiments were carried out at femtosecond laser energy. The experimental results are consistent with the simulation results.

Mass spectroscopic measurement of time-varying ion composition in a pulse-modulated Ar/C4F8/O2 dual-frequency capacitively coupled plasma

The time dependence of the ion composition in pulse-modulated dual-frequency capacitively coupled plasma with Ar/C4F8/O2 was measured using a quadrupole mass spectrometer with an electrostatic energy analyzer. After turning on the pulse, Ar+ ions were preferentially generated, and then, the composition of C x F y + ions, such as C2F4 + and C3F5 + ions, increased. This phenomenon was discussed on the basis of the time variation of electron temperature and the resultant change in the ratio of the C4F8 ionization rate to that of Ar atoms.

Characteristics and suppression methods of low-frequency oscillation in Hall thruster

Low frequency oscillation in the discharge channel of Hall thruster is an important physical phenomenon that affects its performance and stability. In this paper, the characteristics of low-frequency oscillation of the discharge current of Hall thruster and its suppression method are numerically studied by using a one-dimensional fluid model. Assuming that the discharge channel satisfies the quasi-neutral condition, the effects of electron-neutral collision, electron anomalous transport and electron-wall collision on conductivity are considered. The changes of plasma parameters and the effects of magnetic field, preionization rate, and atomic velocity on the amplitude and frequency of discharge current oscillation are also studied. Research results show that the variation of electron temperature in the discharge channel is closely related to the ionization process, and the electron temperature increases as the ionization intensity increases. The fluctuations in neutral gas flow rate and atomic density in the discharge process cause the ionization region to move forward and backward and the ionization intensity to change, which are the main driving forces for the low-frequency oscillation of discharge current in the channel. The magnetic field intensity in the discharge channel affects the axial current by influencing the electron mobility. With the increase of field strength, the oscillation frequency of current decreases, and under different magnetic field strengths, the current amplitude drops as the discharge voltage decreases. When the preionization rate of the working gas increases to above 4%, the amplitude of the discharge current oscillation gradually decreases. When the preionization rate is greater than 3% and the atomic velocity is less than 160 m/s, the discharge current oscillation in the channel exhibits damping attenuation, achieving a stabilizing effect which conduces to stabilizing the discharge of the Hall thruster.

Double Layers in the Earth's Bow Shock

AbstractWe present Magnetospheric Multiscale observations of electrostatic double layers in quasi‐perpendicular Earth's bow shock. These double layers have predominantly parallel electric field with amplitudes up to 100 mV/m, spatial widths of 50–700 m, and plasma frame speeds within 100 km/s. The potential drop across a single double layer is 2%–7% of the cross‐shock potential in the de Hoffmann‐Teller frame and occurs over the spatial scale of 10 Debye lengths or one tenth of electron inertial length. Some double layers can have spatial width of 70 Debye lengths and potential drop up to 30% of the cross‐shock potential. The electron temperature variation observed across double layers is roughly consistent with their potential drop. While electron heating in the Earth's bow shock occurs predominantly due to the quasi‐static electric field in the de Hoffmann‐Teller frame, these observations show that electron temperature can also increase across Debye‐scale electrostatic structures.

Time-Resolved Analysis of the Electron Temperature in RF Magnetron Discharges with a Pulsed Gas Injection

Pulsed gas injection in a plasma can affect many fundamentals, including electron heating and losses. The case of an asymmetric RF magnetron plasma with a pulsed argon injection is analyzed by optical emission spectroscopy of argon 2p-to-1s transitions coupled with collisional-radiative modeling. For a fully detailed population model of argon 2p levels accounting for direct and stepwise electron-impact excitation in optically thick conditions, a rapid decrease in the electron temperature, Te, is observed during each gas injection with the sudden pressure rise. The opposite trend, with unrealistic Te values before and after each pulse, is observed for analysis based on simple corona models, thus emphasizing the importance of stepwise excitation processes and radiation trapping. Time-resolved electron temperature variations are directly linked to the operating parameters of the pulsed gas injection, in particular the injection frequency. Based on the complete set of data, it is shown that the instantaneous electron temperature monotonously decreases with increasing pressure, with values consistent with those expected for plasmas in which charged species are produced by electron-impact ionization of ground state argon atoms and lost by diffusion and recombination on plasma reactor walls.

Investigation on surface morphology and microstructure of double-wire + arc additive manufactured aluminum alloys based on spectral analysis

Double-wire + arc additive manufacturing has gained increasing attention due to the advantage of controlling alloy composition in real time. However, the control mechanisms of microstructure and mechanical properties of high strength aluminum alloys have not been revealed. To solve this problem, in-situ monitoring of double-wire + arc additive manufacturing process were carried out by the spectrograph and a visual sensor. The spectral signal and arc plasma characteristics under different wire feeding rate ratios were systematically studied. Combined with the high-speed photography results of the droplet transfer, it was found that spectral intensities of Mg I 517.26 nm represented abnormally high during the globular transfer process. Surface bulges with the size of about 100 μm were detected. In addition, the microstructure and phase composition of the deposited parts were characterized by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). The results indicated that the variation of electron temperature was consistent with the variation trend of Al2CuMg phase content under different processes. The intensity ratio IRMn/Mg of spectral line Mn I 407.92 nm to Mg I 517.26 nm was proposed to quantitatively measure the degree of phase transformation, which had a better performance than the spectral line intensity and electron temperature. Under the conditions of this research, the phase composition was α(Al) + θ(Al2Cu) + S(Al2CuMg) three-phase when the IRMn/Mg fluctuated around 0.59, and α(Al) + S(Al2CuMg) two-phase produced when the IRMn/Mg fluctuated around 0.35.

Continuous Enhancements of Electron Temperature in the Subauroral Ionosphere Over Eight Days During the 2015 St. Patrick’s Day Storm

AbstractWe have used measurements of the Defense Meteorological Satellite Program (DMSP) satellites to study variations of electron temperature in the subauroral ionosphere during the magnetic storm on 17–25 March 2015. This magnetic storm had a long recovery phase of 7 days, and the ionospheric behavior over the entire storm time was seldom investigated. In this study, we find that the electron temperature at subauroral latitudes was continuously enhanced for 8 days, from the storm onset to the end of the recovery phase. The maximum electron temperature during the storm times was 1000–4000 K higher than the maximum electron temperature during quiet times. This long‐lasting enhancement of subauroral electron temperature was attributed to energy transfer among the solar wind, magnetosphere, ring current, plasmasphere, and ionosphere driven by high‐speed solar wind streams and fluctuating interplanetary magnetic field during the entire 8‐day period of the storm. The electron temperature enhancements were quite symmetric in the post‐midnight sector but became strongly asymmetric near dawn between the southern and northern hemispheres. The asymmetric enhancements of electron temperature near dawn may be related to the magnetic declination and the daytime midlatitude trough in the southern hemisphere. Large daily variations of maximum electron temperature in the post‐midnight sector were observed and may be related to the offset between geomagnetic and geographic latitudes. These DMSP observations provide new insight on ionospheric response to intense magnetic storms.

Lower‐Hybrid Wave Structures and Interactions With Electrons Observed in Magnetotail Reconnection Diffusion Regions

AbstractWe investigate waves close to the lower‐hybrid frequency in 12 magnetotail reconnection electron diffusion region (EDR) events with guide field levels of near‐zero to 30%. In about half of the events, the wave vector has a small component along the current sheet normal, consistent with known lower‐hybrid drift wave properties, but the perpendicular magnetic field fluctuations can be comparable or greater than the parallel component, a feature unique to the waves inside and adjacent to EDRs. Another new wave property is that the wave vector has a significant component along the current sheet normal in some events and completely along the normal for one event. In 1/4 of the events, the term has a significant contribution to the wave electric field, possibly a feature of lower‐hybrid waves more likely to exist in the diffusion region than further away from the X‐line. Electron temperature variations are correlated with the wave potential, due to wave electric field acceleration and crossings at the corrugated separatrix region with different amounts of mixing between reconnection inflowing and outflowing populations. The latter also leads to the anti‐correlation between parallel and perpendicular temperature components. Using four‐spacecraft measurements, the magnetic field line twisting is demonstrated by the correlated fluctuations in and . The lower‐hybrid wave in the EDR of weak guide field reconnection may be generated near separatrices and penetrate to the mid‐plane or locally generated, and the latter possibility is beyond the prediction of previous reconnection simulations.

Potential – Current characteristics of lunar surface at average solar wind conditions

The plasma environment of the Moon is dominated by the solar wind- the most energetic particles from the Sun. In this paper, we present an analysis of Lunar Prospector Electron Reflectometer data from the selected time periods to predict the lunar surface electrostatic potential over the dayside and nightside with respect to the ambient plasma. Here average solar wind condition (when the electron energy is below 100 eV) data was used to predict the surface potential. We used probe theory to derive the potential values. On the dayside, the potential is 5 V and on the nightside, it reaches up to −82 V. The variations in electron temperature (Te) values show strong dependence in the night side potential values. The potential reaches a value of −82 V at Te = 58 eV. Our calculated values agree well with the values measured by the Electron Reflectometer instrument aboard the Lunar Prospector spacecraft. We investigate the variation of the electric field over the two regions and located a transition region on the surface where the potential value is almost zero. This region is most suited for exploration activities, as the region is free from hazards caused by surface charging.

Influence of magnetic filter position on negative ion density in oxygen RF discharge

In this study, the influence of the position of a magnetic filter on electron temperature and hence on the negative ion density in helicon oxygen discharge is investigated. This study is performed with the view to improve negative ion density in radio frequency (RF) plasma. RF plasma is produced in the source region of Helicon Plasma Source (HeliPS) and the variation of electron temperature, density, and negative ion density in case of oxygen discharge is studied to determine the optimum position of the magnetic filter relative to the position of the antenna where RF power is applied. It is observed that the RF field can penetrate beyond the magnetic filter and cause additional ionization in the expansion chamber and thereby produce high energy electrons and decrease the negative ion density. Therefore, the position of the magnetic filter should be sufficiently away from the location of the antenna as it influences the formation of negative ions.

Global model study of plasma parameter variation in helicon plasma source in oxygen discharge

In this work, different plasma parameters, such as electron density, temperature, and negative ion density are measured in both the source and expansion chamber of the Helicon Plasma Source (HeliPS) in a radio frequency (RF) oxygen discharge of 13.56 MHz and are compared with the values obtained numerically using the volume-averaged global model. For this purpose, the global model of RF oxygen discharge suitable for the HeliPS having two chambers (source and expansion) together with the electromagnet in the source chamber and the magnetic cage in the expansion chamber to reduce the radial loss of plasma is developed using the particle and power balance equations. In this model, the radial confinement by the axial field of the electromagnet in the source chamber and the confinement in the expansion chamber by the cusped field of the magnetic cage is incorporated. Studies on the charged particle dynamics by both the model and the experiment show comparable values of the variation of species density and electron temperature with RF power and working pressure as well as with the applied magnetic field of the electromagnet in the source chamber.