Article
Chemistry, Physical
Mengqi Liu, Shuang Xia, Wenjian Wan, Jun Qin, Hua Li, Changying Zhao, Lei Bi, Cheng-Wei Qiu
Summary: Using doped InAs multilayers under moderate external magnetic fields with gradient epsilon-near-zero frequencies, broadband non-reciprocal absorption that can be tailored within the mid-infrared spectral region has been demonstrated. The study of magneto-optical absorption has stimulated diverse energy-technology-related explorations, showing potential in breaking the current theoretical efficiency limits of energy devices compared with reciprocal counterparts. However, experimentally realizing strong infrared non-reciprocal absorption remains an open challenge, and existing proposals of non-reciprocal absorbers are restricted to a narrow working waveband.
Article
Physics, Fluids & Plasmas
E. Belova, N. A. Crocker, J. B. Lestz, E. D. Fredrickson
Summary: Theoretical and numerical studies on sub-cyclotron frequency Alfven eigenmodes (AEs) provide insight into the observed frequency scaling with beam parameters and explain the excitation of global Alfven modes (GAEs) and compressional Alfven eigenmodes (CAEs) in various devices. These modes can be driven unstable through the Doppler shifted cyclotron resonance and can potentially be excited in ITER. Simulations and theoretical predictions demonstrate good agreement with experimental observations, indicating the potential instability of GAEs in larger aspect-ratio devices and smaller beam injection velocities.
Article
Physics, Fluids & Plasmas
Mikhail Viktorov, Alexander Chernyshov, Dmitry Chugunin, Mikhail Mogilevsky
Summary: Electromagnetic emissions above the electron gyrofrequency in mirror-confined electron cyclotron resonance plasma are reported and interpreted as the excitation of the fast extraordinary wave at the fundamental harmonic of the electron gyrofrequency, similar to Earth's auroral kilometric radiation. A method for studying the temporal characteristics of physical processes in the auroral electron acceleration region is proposed and applied to both satellite measurements and laboratory plasma emissions, revealing similarities in cyclotron instability development.
PLASMA PHYSICS AND CONTROLLED FUSION
(2021)
Article
Physics, Fluids & Plasmas
Linzi Liu, Ruihai Tong, Xiaolan Zou, Haotian Chen, Yang Chen, Guanqi Dong, Guangzhou Hao, Xiaoxue He, Yuxiao Han, Xiaoquan Ji, Anshu Liang, Bo Li, Jiquan Li, Yonggao Li, Liang Liu, Zhongbin Shi, Huiling Wei, Fan Xia, Guoliang Xiao, Jiao Yin, Deliang Yu, Boda Yuan, Yiren Zhu, Wulyu Zhong, Min Xu
Summary: Instabilities at multiples of the ion cyclotron frequency have been discovered and termed as core ion cyclotron emission (ICE) in recent HL-2A neutral beam injection heated experiments. This study presents the characteristics of core ICE, including frequency dependence and harmonics features. The observed frequencies are found to be consistent with multiples of the deuterium cyclotron frequency near the magnetic axis. In addition, the core ICE exhibits a predominantly compressional property. The study also demonstrates that the core ICE harmonics represent independent multiple modes, with distinct spectrum features and individual excitation of each harmonic. Notably, the 4th harmonic ICE can be individually excited by varying the plasma current, suggesting a variation in the drive mechanism of core ICE across different frequency ranges.
Article
Astronomy & Astrophysics
A. A. Luzhkovskiy, D. R. Shklyar
Summary: The energization of electrons in the Earth's radiation belts through resonant interaction with whistler mode waves is currently being intensively investigated. The interaction between waves and particles in the Earth's magnetosphere plays a crucial role in determining their dynamics, including wave excitation and damping, as well as particle acceleration and scattering. Resonant particles, which experience a slowly varying force from the waves, can undergo energy transfer through wave-particle interactions. This energy transfer between different groups of particles mediated by whistler mode waves is more efficient than the amplification or damping of waves through resonant interaction with particles.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2023)
Article
Instruments & Instrumentation
Y. Zhu, Y. Chen, J. -h. Yu, C. Domier, G. Yu, X. Liu, G. Kramer, Y. Ren, A. Diallo, N. C. Luhmann, X. Li
Summary: The article introduces the usage of system-on-chip millimeter wave integrated circuit technology for density fluctuation imaging on the DIII-D tokamak fusion plasma, with customized CMOS chips that provide higher performance.
REVIEW OF SCIENTIFIC INSTRUMENTS
(2022)
Article
Geosciences, Multidisciplinary
S. Saito, Y. Miyoshi
Summary: Results from a test particle simulation indicate that electron scattering driven by lower band whistler chorus waves along a magnetic field line is crucial in producing the butterfly distribution of relativistic electrons. Two nonlinear scattering processes, phase trapping and dislocation, contribute to the formation of the butterfly distribution within a minute. Quasilinear diffusion alone is insufficient to reproduce this distribution. The simulation also reveals an upper limit for rapid electron acceleration, suggesting the role of phase trapping in relativistic electron acceleration in the outer radiation belt core.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Astronomy & Astrophysics
Abdul Waheed, M. Fraz Bashir, Anton V. V. Artemyev, Xiao-Jia Zhang
Summary: Plasma sheet electron precipitation to the diffuse aurora is a primary mechanism of energy transport to the Earth's atmosphere, provided by electron resonant interactions with ECH and whistler-mode waves. This paper investigates a third free energy source for ECH and whistler-mode wave generation-the modulation of electron distribution by compressional ULF waves. The statistics and empirical model presented in this paper can be incorporated into simulation frameworks to study the magnetosphere-ionosphere coupling and radiation belt dynamics.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2023)
Article
Computer Science, Interdisciplinary Applications
Yuliang Fu, Juan Yang, Hao Mou, Renwei Tan, Xu Xia, Zhenye Gao
Summary: A two-dimensional full particle-in-cell model is developed to simulate the operation process of a 2 cm electron cyclotron resonance ion thruster. The integrative simulation provides a global perspective to learn the gridded ion thruster, and the response of the plasma system to the accelerating voltage is analyzed. An ion density wave is observed in the plume.
COMPUTER PHYSICS COMMUNICATIONS
(2022)
Article
Astronomy & Astrophysics
Jinsong Zhao, David M. Malaspina, T. Dudok de Wit, Viviane Pierrard, Yuriy Voitenko, Giovanni Lapenta, Stefaan Poedts, Stuart D. Bale, Justin C. Kasper, Davin Larson, Roberto Livi, Phyllis Whittlesey
Summary: This study reports the existence of broadband electrostatic waves below the electron cyclotron frequency in the near-Sun solar wind and solar corona for the first time. These waves may regulate the electron heat flux in the near-Sun solar wind and solar corona.
ASTROPHYSICAL JOURNAL LETTERS
(2022)
Article
Geosciences, Multidisciplinary
Huayue Chen, Rui Chen, Xinliang Gao, Quanming Lu, Yangguang Ke, Zhenyu Kong
Summary: By analyzing Van Allen Probes data for over a year, we studied chorus waves with banded events and without a power gap, and their correlations with the electron plateau distribution. Banded chorus events are typically accompanied by a plateau component with higher number density than no-gap events. The gap frequency is roughly determined by the bulk velocity of plateau components, and the damping at around 0.5f(ce) is caused by cyclotron resonance.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Astronomy & Astrophysics
Takeshi Nogi, Yoshiharu Omura
Summary: We conducted a particle-in-cell simulation to reproduce the triggering process of whistler-mode rising-tone emissions. We found that the rising-tone elements with increasing frequencies are generated through the self-sustaining formation of a long subpacket in the upstream region, which then splits into smaller subpackets during propagation.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2022)
Article
Geosciences, Multidisciplinary
Lunjin Chen, Xiao-Jia Zhang, Anton Artemyev, Vassilis Angelopoulos, Ethan Tsai, Colin Wilkins, Richard B. Horne
Summary: During magnetospheric storms, energetic electron microbursts are observed. It is found that these microbursts may be caused by ducted whistler-mode lower-band chorus waves.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Physics, Fluids & Plasmas
S. Sumida, K. Shinohara, M. Ichimura, T. Bando, A. Bierwage, S. Ide
Summary: This paper discusses the possibility of slow-wave ion cyclotron emissions (ICEs) on the JT-60U tokamak, which may be driven by fast ions rather than fast waves. Through simulations, it is found that fast ions from negative-ion-source neutral beams can destabilize the slow wave, matching observed frequencies of L-ICE.
Article
Astronomy & Astrophysics
J. Joseph, A. N. Jaynes, W. S. Kurth, J. D. Menietti, J. E. P. Connerney, S. J. Bolton
Summary: This study systematically analyzes the ECH waves in Jupiter's inner magnetosphere for the first time, revealing that these waves occur in specific regions and exhibit different intensities. The overlap between the hot injection region and the region of off-equatorial ECH wave occurrence is also noted.
FRONTIERS IN ASTRONOMY AND SPACE SCIENCES
(2023)
Article
Physics, Fluids & Plasmas
I. Izotov, A. G. Shalashov, V. A. Skalyga, E. D. Gospodchikov, O. Tarvainen, V. E. Mironov, H. Koivisto, R. Kronholm, V Toivanen, B. Bhaskar
Summary: Experiments on a minimum-B electron cyclotron resonance ion source revealed the presence of a hump in the energy distribution of escaped electrons at 150-300 keV, which is independent of microwave power but increases with magnetic field strength. The hump formation is likely related to radio-frequency-induced momentum space diffusion, confirmed when microwave power is applied.
PLASMA PHYSICS AND CONTROLLED FUSION
(2021)
Article
Physics, Applied
V. Yu Goryainov, M. E. Viktorov, A. V. Vodop'yanov, A. V. Voronin
Summary: The investigation analyzed the structure of a plasma jet generated by a coaxial plasma accelerator, showing that the radiation intensity oscillates with characteristic frequencies for argon and deuterium. The behavior of the discharge in the accelerator revealed the initiation of a diffuse discharge at the base of the conical insert, eventually contracting and occurring between central and external electrodes. The results can be applied to gas ionization, material irradiation, and simulation of plasma flows interacting with magnetic fields in outer space.
Article
Physics, Fluids & Plasmas
Mikhail Viktorov, Alexander Chernyshov, Dmitry Chugunin, Mikhail Mogilevsky
Summary: Electromagnetic emissions above the electron gyrofrequency in mirror-confined electron cyclotron resonance plasma are reported and interpreted as the excitation of the fast extraordinary wave at the fundamental harmonic of the electron gyrofrequency, similar to Earth's auroral kilometric radiation. A method for studying the temporal characteristics of physical processes in the auroral electron acceleration region is proposed and applied to both satellite measurements and laboratory plasma emissions, revealing similarities in cyclotron instability development.
PLASMA PHYSICS AND CONTROLLED FUSION
(2021)
Article
Instruments & Instrumentation
A. G. Shalashov, E. D. Gospodchikov, T. A. Khusainov, L. V. Lubyako, A. L. Solomakhin, M. E. Viktorov
Summary: This paper describes the hardware developed for the CTS diagnostic for the GDT magnetic trap, which is used in fusion research and reconstructs fast ion distributions driven by high-power neutral beam injection. The diagnostic uses a 400 kW/54.5 GHz gyrotron as a source of probe radiation and employs large-aperture quasi-optical mirror systems for beam formation and scattered microwave radiation collection.
JOURNAL OF INSTRUMENTATION
(2021)
Article
Physics, Fluids & Plasmas
A. G. Shalashov, E. D. Gospodchikov
Summary: The study investigates how ECR plasma heating at a frequency exceeding the minimum electron cyclotron frequency affects the heating effect. It is found that under certain conditions, it may result in the formation of 'butterfly-like' distribution functions of fast electrons.
PLASMA PHYSICS AND CONTROLLED FUSION
(2021)
Article
Physics, Fluids & Plasmas
E. D. Gospodchikov, T. A. Khusainov, A. G. Shalashov
Summary: A method is proposed for tomography of the distribution function of energetic ions using collective Thomson scattering diagnostic data. Measurements of scattering spectra from successive plasma cross sections corresponding to different magnetic-field strengths allow for the restoration of the ion distribution function in velocity space. The problem is reduced to an integral equation of the first kind, which can be solved analytically through various exact and approximate methods.
PLASMA PHYSICS REPORTS
(2021)
Article
Engineering, Electrical & Electronic
L. Lubyako, A. G. Shalashov, A. F. Andriyanov, V. G. Bozhkov, E. D. Gospodchikov, D. S. Dorozhkina
Summary: The set of receiving equipment designed for experiments on the detection of Thomson collective scattering spectra of high-power millimeter-wave radiation in a large-scale open magnetic trap consists of two identical radiometers/spectrum analyzers. Each analyzer has an analysis band of 54.47 +/- 0.55 GHz and a sensitivity of no less than 0.080-0.025 eV, allowing for simultaneous measurements in two independent channels corresponding to different reception angles of the scattered radiation.
RADIOPHYSICS AND QUANTUM ELECTRONICS
(2021)
Article
Physics, Fluids & Plasmas
E. D. Gospodchikov, T. A. Khusainov, A. G. Shalashov
Summary: The electrodynamic reciprocity theorem is employed to study the scattering of finite-aperture microwave beams on density fluctuations in inhomogeneous magnetized plasma. The main result of this study is the representation of the spectral power density of scattered radiation detected by an antenna as a convolution of Wigner functions characterizing arbitrary spatially inhomogeneous distributions of the probe field and the field of the receiving antenna with the spectrum of the autocorrelation function of fluctuations of plasma density. The effects of wave field and medium inhomogeneity are analyzed in different limiting cases. The effective broadening of the scattering spectrum due to inhomogeneity in the planned experiment on collective scattering in the GDT setup is calculated as an example.
PLASMA PHYSICS REPORTS
(2022)
Article
Instruments & Instrumentation
V. A. Skalyga, I. V. Izotov, S. V. Golubev, S. V. Razin, A. V. Sidorov, M. E. Viktorov
Summary: The gasdynamic electron cyclotron resonance (ECR) ion source is a device that achieves ionization efficiency through high plasma density. It provides high-current and high-quality ion beams, making it suitable for applications such as high-current proton injectors. This paper discusses the physical aspects, diagnostic techniques, and future prospects of the gasdynamic ECR plasma.
REVIEW OF SCIENTIFIC INSTRUMENTS
(2022)
Article
Physics, Fluids & Plasmas
A. G. Shalashov, E. D. Gospodchikov, T. A. Khusainov, L. V. Lubyako, A. L. Solomakhin, D. V. Yakovlev
Summary: A fast-ion diagnostic method based on collective Thomson scattering of high-power gyrotron radiation has been developed at the gasdynamic trap facility in Budker Institute. This diagnostic aims to reconstruct the ion distributions over transverse and longitudinal velocities driven by strong neutral beam injection in the plasma core. The first experimental results show that the detected spectra, with an effective noise temperature of about 100 eV, are compatible with early theoretical predictions and can be interpreted as the expected scattering signal from fast ions.
PHYSICS OF PLASMAS
(2022)
Article
Physics, Fluids & Plasmas
A. G. Shalashov, E. D. Gospodchikov, T. A. Khusainov, A. L. Solomakhin, D. Yakovlev, P. A. Bagryansky
Summary: In the experiments conducted at the GDT facility, two different scenarios of plasma discharges were realized by combining ECRH and NBI plasma heating. The first scenario showed a broad distribution of absorbed ECRH power and a stable plasma with improved energy confinement, while the second scenario exhibited a highly peaked electron temperature profile but was susceptible to low-frequency instabilities.
Article
Physics, Fluids & Plasmas
A. G. Shalashov, E. D. Gospodchikov
Summary: In this paper, the structure of radiation from the evanescent layer in inhomogeneous gyrotropic plasma is analyzed for an incident beam with a finite aperture. It is found that the reflected beam has wave distributions with a non-zero angular momentum due to reflection. The helicity of the reflected beam leads to unusual effects in the plasma electrodynamics.
PHYSICS OF PLASMAS
(2023)
Article
Physics, Fluids & Plasmas
A. G. Shalashov, E. D. Gospodchikov, T. A. Khusainov
Summary: In this study, a quasi-optical wave code was combined with a simplified transport model to simulate the time evolution of electron temperature profile during ECR heating. By applying this hybrid code, the bifurcation of narrow and broad microwave heating regimes was successfully simulated and verified in experiments.
PLASMA PHYSICS REPORTS
(2022)
Article
Physics, Multidisciplinary
I. S. Abramov, E. D. Gospodchikov, A. G. Shalashov
Summary: The study demonstrates the possibility of efficiently emitting light in a wavelength range of 11.2 nm +/- 1% by sustaining a discharge in xenon using a subnanosecond terahertz radiation pulse from a modern free-electron laser. This method can achieve a high-intensity extreme ultraviolet radiation with an average power of 35 W, showing potential for applications in experiments using modern free-electron lasers.
JOURNAL OF EXPERIMENTAL AND THEORETICAL PHYSICS
(2021)
