Alfred Wong

A large density cavity that measured 2000 km across and 500 km in height was observed by DEMETER and Formosat/COSMIC satellites in temporal and spatial relation to a new mode of propagation of electromagnetic (em) pulses between discrete magnetic field-aligned auroral plasmas to high altitudes. Recorded positive plasma potential from satellite prob...

Powerful electromagnetic (EM) waves can exert well-defined influence on the atmosphere, ionosphere, and magnetosphere. These active EM interactions can provide spatiotemporal information on the near-Earth space environment (geospace). Objectives include remote monitoring and controlling of a wide range of parameters of geospace, controlling propert...

Laboratory and Field Experiments on Expulsion of Selected Ions along Divergent Polar Geomagnetic Fields. Laboratory experiments have shown significant gyro-resonance acceleration of minority ion species in a magnetized plasma. Field aligned elctron drifts can provide free energy needed to make this process efficient. The linear magnetized device ha...

High Power Auroral Stimulation (HIPAS) Observatory and High Frequency Active Auroral Research Program (HAARP) are two radiating facilities in the Arctic region separated by a distance of the order of VLF wavelengths. The current-carrying plasma in the E region of the ionosphere above each facility can be modulated to radiate VLF waves via HF heatin...

A symmetric neutralized ion beam (SNIB) is composed of positive and negative ions, and is capable of propagating across a transverse magnetic field due to the polarization of the beam. Such a beam may be of use as an alternative or complement to conventional neutral beam injection (NBI) in magnetic confinement fusion devices. SNIBs of energies from...

Cavitons, nonlinear states created by localized enhanced electric fields, can explain the lowering of thresholds in parametric instabilities, the trapping of waves, accelerated electrons and optical emission. With the support of laboratory observation, it is agreed that fast electrons are produced in the vicinity of a density cavity or density stri...

An approach to expel pollutants which can contribute to global warming from the upper atmosphere by the use of HF electromagnetic waves has been proposed [1]. Laboratory plasma experiments have shown significant gyro-resonance acceleration of minority ion species in a plasma is possible. The separation of ions differing in mass by one unit has been...

Experimental results pertaining to the production of symmetric neutralized ion beams (SNIBs) are presented. SNIBs are composed of equal quantities of positive and negative ions and, when they are of sufficient density, are able to propagate across magnetic fields. They may represent an attractive alternative to conventional neutral beams, due to th...

Experiments with symmetric neutralized ion beams consisting of H^+ and H^- ions are being conducted. The H^+ and H^- beams are transported and merged in RF quadrupoles and are then injected into a magnetic field. The ability of the beam to propagate across the magnetic field due to the formation of a polarization electric field that cancels the mag...

A concept to produce negative charges in the stratosphere to disable chlorine radicals in its catalytic destruction of ozone is presented. An outdoor experiment in the Arctic region is described which uses a 200J laser and a 2.7 m rotating mercury mirror to ionize atmospheric dusts to produce the required charges. This large dish will also function...

Neutralized ion beams (NIBs) are composed of positive and negative ions of the same charge-to-mass ratio (D^+ and D^-, for example). The ability of sufficiently dense and energetic NIBs to cross transverse magnetic fields is discussed, and computer modeling as well as experimental results are presented. Radio frequency quadrupole (RFQ) accelerators...

During ionospheric modification, both satellite beacons and sky maps from digital ionosonde measurements have detected large-density perturbation. This perturbation reaches a maximum when the incident HF matches the plasma frequency on the density plateau (or at f_oF2 layer). Experiments and theories are presented which describe how a plasma lens c...

Fusion devices presently employ neutral beam injectors that are very large in size and/or cannot efficiently produce MeV beams. Neutralized ion beams (NIBs) composed of positive and negative ions of the same charge-to-mass ratio might become a more compact and efficient alternative. Presented here is a new approach to the production of modular, hig...

High power HF radiowave pulses launched from ground-based transmitters interact with overdense quies-cent ionospheric plasma to produce strong turbulence effects. These effects are evident in the ion and plasma lines detected by diagnostic radars. Several spatial and temporal signatures in the backscattered plasma lines show reproducible evidence o...

This talk presents a coordinated experimental investigation and computer modeling of basic plasma processes in simultaneous trapping and acceleration of both positive and negative ions by propagating electrostatic structures such as RFQs. The concept of increasing the current through stacking modules will be discussed. Furthermore, the concept of e...

Conventionally, the generation of ELF and VLF radio waves is by amplitude-modulated HF waves interacting with the ionosphere in the presence of electrojet. The electrojet current acts as an antenna, radiating at the modulation frequency. The auroral electrojet is highly dynamic, depending on solar activity and time of the day, making this method hi...

A process of is described which utilizes a nonlinear state "Caviton"(2) to induce localized fusion. Cavitons are depleted-electron-density states created by localized enhanced oscillating fields. The large ambipolar potential results in the acceleration and trapping of D- to fuse with D+. Cavitons can be created efficiently because the enabling osc...

This paper presents experimental results derived from NOAA HF radar (dynasonde) measurements, done during the 1992 ionospheric modification campaign (Campaign’92) conducted at the UCLA HIPAS facility near Fairbanks, AK. During this campaign, the HIPAS transmitter illuminated the ionosphere with high frequency electromagnetic waves at 2.85 and 4.53...

The spatial, spectral, and statistical properties of the high-frequency (ω ∼ ωpe) electrostatic fluctuations in an unmagnetized, statistically stable, beam-driven, strongly turbulent plasma are investigated experimentally and the results are compared to the two-component model of Robinson and Newman. The fluctuations are found to consist of low-lev...

The scattering of an electron beam in angle and energy in an unmagnetized, statistically stable, strongly turbulent plasma is investigated experimentally and the results are compared to a theoretical model derived using the Born approximation and the two-component model of strong Langmuir turbulence. It is found that for a typical wave intensity le...

This review talk describes how basic science finds application in space, fusion, environmental remediation and plasma processing. Basic plasma science deals with a hierarchy of interactions from single particle to collective motion in a many-bodied system. The physics of wave–particle interaction stimulates new applications to fusion and space prop...

We present the results of three-dimensional fully kinetic simulations of UCLA laboratory experiments,(A. Y. Wong and P. Y. Cheung, Phys. Rev. Lett.), 52, 1222 (1984) which were the first experiments to show Langmuir-wave collapse in a beam-driven plasma. Our massively-parallel particle-in-cell (PIC) simulations model the continuous injection of a f...

Strong Langmuir turbulence (SLT) is marked by density cavities driven by ponderomotive force and by spatial and temporal self-focusing (collapse) of nonlinear wavepackets trapped in these cavities. SLT is a distinctive and fundamental nonlinear state of a plasma which has been driven in laboratory plasmas by weak, nonrelativistic electron beams (1,...

In high latitude ionosphere, the traditional way to generate the ELF/VLF signal is by modulating the pump frequency with the presence of the electrojet. A new technique is introduced to generate the ELF/VLF signals by sweeping the pump frequency starting at or near the peak of the ionospheric E layer. This new technique utilizing the frequency agil...

Experiments are described on the simultaneous trapping and acceleration of both positive and negative ions by propagating electrostatic structures in plasmas. As the velocity of an electrostatic structure is increased, the ions trapped in its electrostatic wells are accelerated. The symmetry between positive and negative ions requires that ions of...

Freely propagating electrostatic waves (free modes) are observed to be produced by intense, localized field structures in laboratory measurements performed in an unmagnetized plasma in a state of strong Langmuir turbulence. The freely traveling waves conform to the Langmuir dispersion relation and have an average frequency which is approximately 11...

We have performed an experiment to artificially stimulate the ionosphere using higher power radio waves at the HIPAS (High Power Auroral Stimulation) facility in Alaska. A radio transmission of 2.85 MHz was made at 80 MW (ERP). Diagnostics were made at the other site located 35 km from the transmission site. The results of cross-correlating the exc...

The arctic sodium layer is routinely monitored with a 11 Watt-m^2 lidar at the HIPAS Observatory. The lidar is timed so that the Na layer is probed during an off cycle of a square wave modulation pattern of the 70 MW - ERP 2.85 MHz radio frequency (RF) heater at HIPAS; eliminating false counts by the lidar. During a recent (March 1999) HAARP campai...

Experimental results illustrating maximum density modification near the peak of the ionospheric density profile using the HIPAS facility are presented. The amplitude and the frequency spectra of the reflected pump waves are studied. The heating effects were observed to be maximized when the pump frequency matches the peak plasma frequency of the io...

A device is being constructed to produce high density quiet plasmas for materials processing. The device consists of a solenoid magnetic field of strength up to 10 kG, and a 1.2 m long vacuum system. The plasma is produced by ECRH at either 10 GHz, or 18 GHz, with the resonance zone located on one end of the device. Plasma can be made from any gas...

The ionosphere provides us with an opportunity to perform plasma experiments in an environment with long confinement times, very large-scale lengths, and no confining walls. The auroral ionosphere with its nearly vertical magnetic field geometry is uniquely endowed with large amount of free energy from electron and ion precipitation along the magne...

A novel particle acceleration is being constructed. The device accelerates particles by nonlinear wave-particle interaction. The particles to be accelerated are trapped within an accelerating wave structure maintained by externally imposed boundary conditions. As the phase velocity of the wave is increased the particle velocity increases. Additiona...

Experimental measurements performed in an unmagnetized plasma with a cold electron beam as the free energy source reveal the development of localized, large amplitude, electrostatic field structures at sharp, downward-going gradients in the plasma density. The relative intensity of the spiky field structures is found to correlate with the reciproca...

New results of stimulated electromagnetic emissions (SEE) from the HIPAS Observatory are reported. A novel hf heating sequence was used to first pre-condition the ionosphere and SEE was then excited with low amplitude test pulses. Through this approach, the nonlinear physics of SEE generation has been studied and the correlation between striations,...

Plasma production from solid targets starts at 10^8W/cm^2. Such fluxes can be realized at 10-100 km ranges with 10-100 J/pulse - one ns infra red solid state lasers when the output beam is expanded and focused by a 3 m diameter parabolic reflector. Raman shifting a 1.06mu Nd^+ laser in H2 gas to 1.9mu minimizes atmospheric effects and results in a...

An existing high power plasma dissociator system, operated by UCLA at the HIPAS facility in Fairbanks Alaska, is used to examine the scaling laws by which similar systems can be operated. This system dissociates a gas stream using a rf field. The main use for such systems is for treatment of mixed and hazardous waste streams. The target of this res...

Recent results of ionospheric modification experiments at the HIgh Power Auroral Studies (HIPAS) Observatory indicate that preconditioning of the ionosphere by HF pumping reduces the threshold power needed to observe nonlinear plasma phenomena such as Stimulated Electrostatic Emission (SEE) spectra. After long pulses of the HF transmitters, SEE is...

The 2.7 meter diameter parabolic Liquid Mirror Reflector (LMT) at the HIPAS Observatory could focus a 1060 nm pulsed laser beam to a 4 cm spot size over a Rayleigh focal range of 1.2 km ( 1.4 m3 focal volume). A 100 J - one nanosecond laser pulse (1011 Watt) would result in an ideal flux of 1.7x1010 W/cm2 at 100 km range, two orders of magnitude ab...

New measurements of stimulated electromagnetic emissions (SEE) in low duty cycle heating experiments performed at the HIPAS Observatory are presented. Two distinct types of spectra, a weak diffuse type and a stronger type with deep frequency modulations, were observed. These results have been compared with numerical predictions from a 1D driven and...

The detailed spectral content of strong Langmuir turbulence generated by an electron beam is investigated experimentally in an unmagnetized plasma. It is found that the power spectra of the electrostatic waves follows a consistent, reproducible pattern in which the Langmuir energy is concentrated in high frequencies (410 MHz) immediately following...

The auroral Borealis is Nature's most colorful display of plasma physics = in the polar region. This talk will describe the free energy sources in = terms of particle precipitation and associated current in the polar magnetic = field responsible for such phenomena. A "High Power Auroral Stimulation" = (HIPAS) facility in Alaska has been used to act...

Results are presented from recent experiments that employ high-power, high- frequency (HF) radio waves to probe the mesosphere and lower thermosphere. The measurements were made at the High-Power Auroral Stimulation (HIPAS) Observatory located near Fairbanks, Alaska. One objective of the study was to determine the feasibility of using artificial el...

A Na mesospheric density lidar or `guide star' illuminator can be tuned by visually observing the pattern of laser- induced fluorescence inside a Na illumination lamp soon after it has been turned off. Optimum tuning occurs when the fluorescence is trapped inside the lamp and appears to fill the bulb as a whole.

We report experimental results from the high-power auroral simulation facility showing that the lower D region can be heated so as to produce either a single, narrowband ELF/VLF radiation signal at the modulation frequency or a signal containing the modulation frequency and many odd harmonics. The measurements are compared to a new 2 1/2-dimensiona...

The UCLA RF Plasma Dissociator is an inductively coupled plasma device, developed for the dissociation of simulated hazardous waste with either inert (Argon) or oxidizing (air) carrier gases at atmospheric pressure. The rf coil (15 cm length, 8.9 cm diameter) operates at 2.85 MHz with power ranging from 40 to 85 kW. Plasma temperature and density h...

Charged water droplets, approximately 100 microns in diameter, have been generated with a "droplet generator" consisting of a pressurized reservoir, a 50 micron diameter orifice, and a piezoelectric driver. The liquid jet (in air at STP) breaks up into uniform droplets, inside an electrically biased pipe which inductively charges the droplets to th...

First results of broadband stimulated electromagnetic emissions (SEE) near the second electron cyclotron harmonic (2Omega_e) are presented. The results were obtained at a recent HF heating campaign at the HIPAS Observatory with the heater frequency omegao near 2Omegae at 2.85 MHz. Experiments were performed for both O and X-mode polarizations, and...

An ECRH plasma source has been constructed within a 10 kG solenoid, using a 10 kW (max) of CW 10.6 GHz klystron amplifier. Vacuum base pressures are on the order of 10-7 torr. One kW of CW ECRH microwave power is sufficient to create a high density (10^12 cm-3) fully ionized pure calcium metal plasma, the maximum theoretically possible at 10.6 GHz....

Systematic correlation of ELF and VLF signal strenghts with spatial distributions of electrojet and auroral arcs has been investigated in a series of experiments carried out using the HIPAS heater array (f0 = 2.85 MHz, P_rad ~= 800 kW). The heater beam was scanned along the magnetic N-S direction and ELF/VLF signals were aquired with the magnetomet...

A lidar system consisting of a 2.7 m diameter rotating mercury collector and a 7 mJ/pulse 10 Hz excimer pumped dye laser tuned to the Na-D2 (589 nm), resonance, has been installed at the HIPAS Observatory, Alaska (65^circN-147^circW). The lidar passes under the electrojet and the aurora. It is inside an arctic building with a glass skylight for win...

The removal of ozone destroying atomic chlorine or its reservoirs by atmospheric electrical charging is reviewed for three different heights and regimes. Atmospheric electrification provides electrons which can attach to chlorine atoms of high electron affinity, inhibiting its catalytic destruction of ozone. In one scheme electrons are emitted from...

The characteristics of three different modes of ELF and VLF excitation using the high-power auroral simulation (HIPAS) HF heater array are compared under different ionospheric conditions. For each of these three methods, amplitude modulation (AM), phase demodulation (DM), and the double-frequency excitation (DF), we observed signals on the order of...

We report the double resonance excitation of two pump waves with frequencies separated from 5 to several hundred Hz. The cyclotron frequencies of NO+ and O+2, abundant at the bottom of the F layer (~150 km), are within this range. The nonlinear mode coupling takes place at ~150 km where the pump frequency matches the plasma frequency. The experimen...

The optical diagnostic technique of laser‐induced fluorescence has been applied to a low pressure nitrogen discharge generated by radio frequency waves. The first negative system of N⁺ 2 was investigated with the use of a tunable dye laser. The radiative lifetimes of the B²∑⁺ u (v’=0,1) levels were measured to be 65...

The N2 C 3Piu lifetime was measured by laser-induced fluorescence (LIF) in a low-density plasma. To take account of radiation trapping efects, the lifetime was measured as a function of LIF signal amplitude, which is also a measure of the N2 B 3Pig density. To first order, radiation trapping is linearly proportional to B-state density. By extrapola...

The balance of energy and angular momentum is modeled for a rigid-rotor plasma equilibrium generated by a rotating magnetic field. The model predicts that deviation from circular polarization of the rotating field and the presence of transverse stationary error fields reduce the efficiency of the diamagnetic current drive. The error field in combin...

Variations in electron temperature in a pulsed radio‐frequency nitrogen plasma have been investigated with a floating double‐Langmuir probe and by laser‐induced fluorescence. Observations suggest that the N 2 (B ³Π g ) level is populated by excitation from the metastable N 2 (A ³Σ⁺ u ) level by low‐energy electrons.

Experiments in large chambers demonstrate for the first time the recovery of ozone after catalytic destruction by chlorine atoms released from CFCl3 under uv radiation. Recovery is brought about by charge attachment to chlorine atoms which encounter a current of low-energy negative charges. These negative chlorine ions do not destroy ozone catalyti...

Laser‐induced fluorescence from a low‐pressure, magnetized, radio‐frequency‐generated plasma was observed for the first negative (1N) system of N⁺ 2 (B²Σ⁺ u -X²Σ⁺ g ). A tunable dye laser was used to excite the 1N system in the (0‐0) and (0‐1) transitions; individual rotational lines in the R b...

In a high-power microwave-plasma system, it has been experimentally found that electromagnetic (em) radiation at subharmonic frequencies [specifically, (3/2)?0 and (5/2)?0] of the electron plasma frequency of the unperturbed state, ?0, can be emanated from cavitons which are resonantly driven by an intense em pulse (frequency ?0) in an unmagnetized...

During this contract period, the work performed at the HIPAS site can be divided into two categories. The first category is basic site maintenance and the second category is experimental and scientific endeavors. The harsh weather at the HIPAS site combined with the remote location greatly increase the sight maintenance requirements. There are furt...

This paper reports the results of the first concerted effort (both experimentally and theoretically) to characterize the various parameters of the Extremely Low Frequency (ELF) and HIgh Power Auroral Stimulation (HIPAS) polar electrojet antenna excited by the HIPAS radiating facility. These parameters include the magnetic dipole moment, excitation...

Nitrogen laser-induced fluorescence from a low-pressure (≤10−3 torr) radio frequency produced plasma has been observed for the second positive system of N2. A 45.4±0.4 ns lifetime of the C 3&Pgr;u(v’=0) state was experimentally measured from laser-induced fluorescence. In addition, some transition probabilities of the second positive system were de...

The final, nonlinear, saturated state of the diocotron instability is investigated experimentally in a magnetized, annular, nonneutral plasma. As the wave grows to large amplitude, the plasma is organized into vortices. In the limit of high magnetic fields, and moderate central conductor biases, the diocotron modes compress the plasma into dense (n...

The catalytic destruction of ozone by CFC was quantitatively measured in a large laboratory device which has controlled ultraviolet radiation and gas composition. Experimental results obtained in a pure oxygen atmosphere agreed with theoretical estimates within a factor of two. A destruction ratio of one chloride to 4 × 105 ozone molecules was foun...

A very intense electron plasma wave is resonantly excited at the top of a broad, flat density profile, by a longitudinal very-high-frequency electric field oscillating at the plasma frequency. Electric field energy densities {ital W}={ital {tilde E}} {sup 2}/4{pi}{ital n}{sub {ital c}T{ital e}}{gt}10{sup 3} are produced, along with copious electron...

Strong Langmuir turbulence effects are investigated during ionospheric modification experiments performed at the Arecibo Observatory. Indirect evidence of Langmuir wave collapse is obtained through the observation of theoretically predicted 'caviton-type' enhanced plasma wave spectra. A typical spectrum consists of a 'free-mode' peak with a frequen...

Steady-state quiescent field-reversed configurations are produced in the toroidal UCLA RACETRACK (Rev. Sci. Instrum. {bold 57}, 2720 (1986)) by rotating magnetic fields. Observed pressure and magnetic field profiles agree with high β, rigid electron rotor theory. Full penetration of the right-hand component of the rotating field and slight ion dra...

A review of current and a discussion of future experimental techniques is presented in the study of ionospheric plasmas. The ability to induce large-scale changes in the ionosphere by high-power ground-based HF transmitters makes it possible to perform laboratory-like experiments repetitively in space plasmas. The plasma can be investigated using s...

We report the successful generation and detection of ELF waves in the frequency range of 6-76 Hz by polar electrojet modification using the High-Power Auroral Stimulation (HIPAS) HF Heater Facility near Fairbanks, Alaska. Magnetic field amplitudes of-1 pT and vertical electric field amplitudes of---0.2 mV have been observed at a receiving site 35 k...

UCLA's RF ionospheric heater, 40 km east of Fairbanks, Alaska, consists of eight crossed dipole antennas arranged in a circular pattern to give a gain of 18.4 dB over isotropic at 2.85 MHz. At 1.2 MW total radiated power, the array has a calculated equivalent radiating power of 84 MW. The eight transmitter antennas are managed by a PC which control...

Stimulated EM emissions of the auroral ionosphere in the vicinity of Fairbanks, Alaska, have been observed during high-power HF heating experiments. Asymmetric spectra around the heater frequency with dominant lower sidebands are observed under conditions of very long density scale lengths corresponding to f(0)F1 transition of the heater frequency....

and antenna directivity resulted in a power density of the order of 1 mw/m2 at E layer heights and 0.2 mw/m 2 at F layer heights. O mode polarization was used for heating at a frequency of 2.85 MHz. Effects were observed at both E and F layer heights. The F layer effects consisted of enhanced attenuation, modified group delay at frequencies above a...

A new diagnostic consisting of a high-power RF or microwave transmitter and a ground-based lidar system is proposed for probing the ionosphere at heights of 80-200 km. The high-power transmitter creates energetic electrons in the ionosphere, which excite molecules to higher energy levels. These excited molecules become targets for a laser ranging s...

We have investigated several phenomena of importance to laser-plasma interactions. In our studies, these are modeled by microwave and rf-plasma interactions. Our focus has been on resonant absorption of intense electromagnetic radiation at the plasma critical layer. Electron plasma wave (EPW) growth and caviton formation have been shown to be most...

The effect of a zeroth-order density gradient on the development of cavitons has been investigated experimentally and numerically. The cavitons were produced via excitation of electron plasma waves (EPW) with a modest resonant radio-frequency pump. The location of the resonance, on an inverse-parabolic density profile, was varied, with all other pa...

Summary form only given, as follows. A steady-state field-reversed-configuration was generated by the rotating magnetic field (RMF) technique in a straight section of Racetrack. The plasma equilibrium is of the rigid rotor type. The effects of RMF current drive on particle, energy, and momentum transport were studied. The total power input by the m...

Linear and nonlinear absorption of electromagnetic waves in a warm, magnetized, nonuniform plasma is studied using an electromagnetic particle simulation code (ZOHAR) with either 1 or 2 spatial and 3 velocity dimensions. With fixed ions, finite temperature, and finite wave amplitude, transmission of the ordinary mode to the slow extraordinary wave...

Stable, steady-state plasma equilibrium is generated in an axisymmetric configuration. The diamagnetic current is maintained by electromagnetic fields rotating in the electron diamagnetic sense. The stable, free-standing equilibrium exists for all values of beta up to 0.98, limited only by the available rf power. The plasma is centered on the axis...

Large-scale density modification was optimally achieved by electromagnetic waves whose frequency matched the plasma frequency at a height where the ionospheric density profile was flat. The density in this region was dramatically clamped during the morning when it normally increases from solar ionization. Electromagnetic wave propagation in the pol...

A Comment on the Letter by Cheung {ital et} {ital al}., Phys. Rev. Lett. 62, 2676 (1989).

Power deposition profiles derived from measured equlibrium and field-penetration profiles in the RACETRACK rotating magnetic field drived FRC are presented. It is found, that significantly higher RF power can be deposited in the plasma than what is necessary to maintain the diamagnetic current. The Klima relations are reconciled with the higher pow...

The curvature-driven interchange mode is stabilized by spatially modulating the magnetic field lines at the plasma surface. This is effected by a high-order multipole field. No radial magnetic well is created, and axisymmetry is retained throughout most of the volume. The density, plasma lifetime, and pressure gradient increase by an order of magni...

We have investigated several phenomena of importance to laser-plasma interactions that are associated with cavitons generated at the critical layer of a nonuniform plasma by resonant absorption of intense electromagnetic radiation. The emission, from deep cavitons, of electromagnetic radiation at half-harmonics of the pump frequency, has been exami...

Several phenomena of importance to laser-plasma interactions that are associated with cavitons generated at the critical layer of a nonuniform plasma by resonant absorption of intense electromagnetic radiation were investigated. The emission, from deep cavitons, of electromagnetic radiation at half-harmonics of the pump frequency, was examined. Cav...

The transition to chaos through intermittency has been observed in a steady-state plasma system. Results from real-time signals, spectral analysis, and constructed Poincaré sections are used to confirm the existence of intermittency. Low-frequency 1/f-type noise is also observed during the onset of chaos.

High-frequency parallel electric fields applied to plasmas confined in a simple magnetic mirror cause enhanced plasma loss. The plasma potential rises because of a population of electrons in the magnetic loss cone that are accelerated to parallel energies significantly higher than the bulk electron temperature. The radio-frequency induced plasma lo...

The stabilization of the diocotron instability by an applied radial dc electric field in an annular magnetized pure electron plasma is investigated experimentally. The radial electric field E(r) from the annular plasma gives rise to a radially dependent azimuthal E(r)×Bz drift. The shear in this drift provides the free-energy source for the instabi...

We report the first experimental observation of chaotic behavior and period doubling in a pulsed plasma discharge sensitive to initial and boundary conditions. The Feigenbaum constants have been measured experimentally in one of the observed chaotic discharge routes.

The observation of the change in the ionospheric density profile and the creation of a density cavity at the critical height by high-power radio waves is made by the time-of-flight radar scattering technique. Small-scale cavitons imbedded inside a large caviton are inferred from the suppression of the photoelectron-enhanced plasma lines near the cr...

The construction and operation of a novel magnetized plasma device are described. The device combines characteristics of both linear mirror and toroidal confinement. It opens up new areas of basic plasma physics research. Examples of experiments on potential formation are presented.

The axial confinement time of a single cell mirror is found to be proportional to the mirror ratio over the range of 12–74 when the mean free path for Coulomb collisions is less than one-third of the length of the device. The reduction in total end-loss current is shown to correspond to the reduction of the cross-sectional area of the plasma at the...

We have observed three new phenomena associated with cavitons generated at the critical layer in an inhomogeneous plasma. Half-harmonic ((1/2)..omega..â, (3/2)..omega..â, etc.) electromagnetic (em) radiation, accompanying the resonant absorption of the high-power microwave at ..omega..â by an inhomogeneous plasma, appears to originate from the cavi...

This report discusses research on the following magnetic mirror configurations: Racetrack; ECRH generated plasmas; RF generated plasmas; potential structures; surface multipole fields, and lamex; hot electron physics; axial loss processes; and RF induced effects.

Experimental measurements on the long-time evolution of strong Langmuir turbulence in a beam-plasma system reveal a picture of periodic, short bursts of Langmuir wave collapse instead of the existence of long-lived solitons. The remnants of density cavities from burnout cavitons are observed to curtail wave growth periodically, creating time interv...