Since 1986, the centre solenoid (CS)-less formations of ultra-high-beta CT/ST plasmas have been developed in TS-3 merging experiment using high power heating magnetic reconnection. In cohelicity (Type-A) merging, two STs were merged together to build up plasma beta βT≈0.5. counterhelicity (Type-B) an oblate FRC formed by spheromaks with opposing toroidal field Bt, was transformed into (βT≈0.8) ST applying external Bt. We made BALLOO code stability analyses produced and concluded that...

Spontaneous formation of toroidal flow was measured for the first time in oblate field-reversed configurations (FRCs) produced TS-3 and TS-4 experiments. The ion (Vi ≈ 10 km s−1) found to peak around magnetic axis, indicating that FRC had a peaked current sharp contrast its hollow electric current. also indicated high shear inside separatrix. observed deform field lines FRC, producing bipolar profile. In high-s (averaged number gyro-radii separatrix: `s' = 4.5) with slow flow, n 1 mode kept...

The wave number spectrum (one-dimensional spectrum) of electrostatic potential fluctuations at sub-Larmor scales was measured in two-dimensional (2D) turbulence laboratory magnetized plasma. ${k}_{\ensuremath{\perp}}{\ensuremath{\rho}}_{i}>1$, where ${k}_{\ensuremath{\perp}}$ and ${\ensuremath{\rho}}_{i}$ are the fluctuation perpendicular to magnetic field ion Larmor radius, respectively, supports existence ${k}^{\ensuremath{-}10/3}$ inertial range entropy cascade induced by nonlinear phase...

This paper presents a newly developed lithium plasma emitter, which can provide quiescent and low-temperature collisionless conditions for magnetized experiments. emitter generates thermal emissions of ions electrons to produce plasma. Lithium type beta-eucryptite lanthanum-hexaboride (LaB6) powders were mixed directly heated with tungsten heater synthesize ion electron emissions. As result, diameter ∼15 cm was obtained in magnetic mirror configuration. The typical range density 1012–1013...

We report the first experimental identification of new wave branch at electron cyclotron frequency produced by injection a frequency-matched intense pump in magnetized plasma [A. G. Litvak and M. D. Tokman, Phys. Rev. Lett. 88, 095003 (2002); Shvets J. S. Wurtele, 89, 115003 (2002)], which is classical phenomenon analogous to electromagnetically induced transparency (EIT) quantum systems. By using frequency-sweep interferometer, we directly detected dispersion relation EIT for propagation...

Abstract The turbulence of collisionless magnetized plasmas, as observed in space, astrophysical, and magnetically confined fusion has attracted considerable interest for a long-time. entropy cascade plasmas is theoretically proposed dynamics comparable to the Kolmogorov energy fluid turbulence. Here, we present evidence an laboratory by direct visualization distribution phase space experiments. This measurement confirms scaling laws predicted gyrokinetic theory with dual self-similarity...

This study presents a simple and powerful technique for multichannel measurements of the density profile in laboratory plasmas by microwave interferometry. uses electromechanical switches to temporally switch connection between multiple receiver antennas one phase-detection circuit. Using this method, phase information detected at different positions is rearranged into time series that can be acquired from minimum number data acquisition channels (e.g., two case quadrature detection). Our...

We report the observation of electromagnetic radiation at high harmonics electron cyclotron frequency that was considered to be converted from electrostatic waves called Bernstein (EBWs) during magnetic reconnection in laboratory overdense plasmas. The excitation EBWs attributed thermalization electrons accelerated by electric field around X-point. radiative process discussed here is an acceptable explanation for observed radio pulsation associated with major flares.

This study derives the electric susceptibility tensor of a cold magnetized plasma under electromagnetically induced transparency (EIT) regime (Litvak and Tokman 2002 Phys. Rev. Lett. 88 095003, Shvets Wurtele 89 115003) in which an intense right-hand circularly polarized pump wave is injected parallel to background magnetic field. A dispersion relation electron cyclotron frequency range for arbitrary propagation angle obtained from this tensor. In case purely probe wave, by Litvak, others...

This paper derives a wave equation in magnetized plasma under electromagnetically induced transparency (EIT) regime for probe electron cyclotron wave. The has solution indicating state analogous to “dark-state polaritons” [M. Fleischhauer and M. D. Lukin, Phys. Rev. Lett. 84, 5094 (2000)] quantum atomic system. dark-state polaritons is propagating coupled of the probe-wave electric field longitudinal oscillation. propagation can be stopped as its waveform maintained if injection pump...

A transition from Langmuir wave turbulence (LWT) to coherent supercontinuum (LWSC) is identified in one-dimensional particle-in-cell simulations as the emergence of a broad frequency band showing significant temporal coherence field accompanied by decrease von Neumann entropy classical fields. The concept utilized for evaluation phase-randomizing degree fields, together with introduction density matrix LWT LWSC takes place when energy per one plasmon (one quantum) exceeds certain threshold....

Abstract Axial merging of two torus plasmas is utilized as a center-solenoid free start-up scheme for high-beta spherical tokamak (ST) plasma, in which magnetic reconnection under strong guide field plays dominant roles energy conversion and equilibrium formation. The ion heating source the plasma outflow with <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi>E</mml:mi> <mml:mo>×</mml:mo> <mml:mi>B</mml:mi> </mml:mrow> </mml:math> drift velocity...

We propose a method for reconstructing the fluctuation components of electron velocity distribution function f(v_perp), and entropy, which is functional f(v_perp) expressed as -f(v_perp)lnf(v_perp)dv_perp, using harmonic spectrum from pure X-mode cyclotron emission (ECE) in optically thin plasmas. Here, v_perp represents perpendicular to background magnetic field. This formulation employs maximum entropy space Hankel transform, converts p (where index wavenumber space). Numerical tests...

Abstract We propose a method for reconstructing the fluctuation components of electron velocity distribution function (EVDF), and entropy, which is functional EVDF, using harmonic spectrum from pure X-mode cyclotron emission (ECE) in optically thin plasmas. This formulation employs maximum entropy space Hankel transform, converts v ⊥ to p (where, are perpendicular background magnetic field index wavenumber space). Numerical tests validated effectiveness proposed method, applicable across...

We report the observation, in a particle-in-cell simulation, of phenomenon which magnetized plasma absorbing an electron cyclotron wave is rendered transparent by pump wave, classical analog to electromagnetically induced transparency (EIT) quantum physics. Evident mode coupling between probe and driving longitudinal oscillation, required for realization EIT, identified addition observation recapturing propagation plasma.

Solitary drift waves (SDWs) in magnetized plasmas were discovered and then first investigated by experiment numerical simulation the Kyushu University group [i.e., H. Arakawa et al., Plasma Phys. Controlled Fusion 52, 105009 (2010)]. However, formation mechanisms of SDWs still await thorough examination. Our work experimentally identifies a clear transition from turbulent (DWs) to for varied radial gradients background density, which is agreement with preceding simulations [M. Sasaki Plasmas...

We present a demonstration of electromagnetically induced transparency (EIT) in magnetized plasmas by means experiment and numerical simulation. EIT is phenomenon which plasma-absorbing electron cyclotron wave rendered transparent pump wave, classical analog to conventional quantum although the plasma not quantum-mechanics-based phenomenon. This paper describes an attempt identify oscillations excited mode coupling probe key mechanism for achieving EIT, particle-in-cell (PIC) A preliminary...

A numerical code has been developed to treat the mode conversion process between electromagnetic and electron Bernstein waves for arbitrary propagation angle polarization considering real experimental configurations on various devices. Robustness of any heating/detection condition with change plasma parameters or frequency can be also estimated this in a short time.

Ring-averaged velocity distribution function of ions at a fixed guiding center position is fundamental quantity in the gyrokinetic plasma physics. We have developed diagnostic tool for ring averaged laboratory experiments, which named as ring-averaged ion probe (RIDFP). The RIDFP set collectors different velocities. It designed to be immersed magnetized plasmas and achieves momentum selection incoming by Larmor radii. To nullify influence sheath potential surrounding on orbits ions,...

Significant amount of collisional scatterings non-thermal electrons accelerated by magnetic reconnection electric field was identified outside the diffusion region in a high-guide-field experiment using spherical tokamak plasma merging. Electron cyclotron emission (ECE) measurement and orbit calculations clarified that enhanced ECE observed during event stemmed from gyro-motions having high perpendicular energy generated through parallel acceleration scattering background ions. The efficient...

A thermodynamic formulation of one-dimensional, weak Langmuir-wave (LW) turbulence is presented. nonlinear Schrödinger equation, which has a non-local interaction term stemming from Landau damping, considered as model equation. By considering the damping system-bath interaction, non-equilibrium counterpart canonical picture applied to weakly LWs. The background equilibrium electrons are regarded heat bath in contact with wave-turbulence system (the perturbation part electron probability...