Plasma Physics

The Quasi-Poloidal Stellarator (QPS) is being developed to test key physics issues at very low plasma aspect ratio, 1/2-1/4 that of existing stellarators. Engineering innovation is driven by both the complex 3-D design requirements and the need for reduced cost and risk in fabrication. Complex, highly accurate stainless steel modular coil winding forms are cast and machined; conductor is wound

Realistic simulations of electric current excitation in three-dimensional vessel structures by the plasma touching the walls are necessary to understand plasma disruptions in tokamak. In large tokamaks like ITER, the wall-touching kink modes cause large sideway forces on the vacuum vessel determined by the sharing of asymmetric electric current between the plasma and the wall. Our model covers both eddy currents, excited inductively by vertical modes, and source/sink currents due to current sharing between the plasma and the thin conducting wall. The developed finite element approach calculates the electromagnetic wall response to perturbation of magnetic fields and to current sharing between the plasma and the wall. The current density entering/exiting the wall surface from the plasma and the time derivative of the magnetic vector potential of the plasma are the input values. The magnetic field and the vector potential from the wall currents are returned as output. Our model has been checked against analytical examples of a multiply-connected domain of a real ITER wall.

The understanding of plasma disruptions in tokamaks and predictions of their effects require realistic simulations of electric current excitation in three-dimensional vessel structures by the plasma touching the walls. As discovered at JET in 1996 (Litunovski JET Internal Report contract no. JQ5/11961, 1995; Noll et al., Proceedings of the 19th Symposium on Fusion Technology, Lisbon (ed. C. Varandas & F. Serra), vol. 1, 1996, p. 751. Elsevier) the wall-touching kink modes are frequently excited during vertical displacement events and cause large sideways forces on the vacuum vessel which are difficult to withstand in large tokamaks. In disruptions, the sharing of electric current between the plasma and the wall plays an important role in plasma dynamics and determines the amplitude and localization of the sideways force (Riccardo et al., Nucl. Fusion, vol. 40, 2000, p. 1805; Riccardo & Walker, Plasma Phys. Control. Fusion, vol. 42, 2000, p. 29; Zakharov, Phys. Plasmas, vol. 15, 2008...

In this paper we present two equilibrium solvers for axisymmetrical toroidal congurations, both based on the expansion in poloidal angle method. The rst one has been conceived as a two-point boundary value solver in a system of coordinates with straight eld lines, while the second one uses a well-conditioned Cauchy formulation of the problem in a general curvilinear coordinate system. In order to check the capability of our moment methods to describe equilibrium accurately, a comparison of the moment solutions with analytical solutions obtained for a Solov'ev equilibrium has been performed.

The contents of this preprint and all other JET EFDA Preprints and Conference Papers are available to view online free at www.iop.org/Jet. This site has full search facilities and e-mail alert options. The diagrams contained within the PDFs on this site are hyperlinked from the year 1996 onwards. 2. operAtIon of Jet wIth the Iter-lIke wAll. 2.1 Plasma imPurity content and imPurity sources from Plasma facing comPonents From the very first JET-ILW plasmas the impurity content has been significantly reduced as compared to JET-C conditions. The carbon content is on average a factor 20 lower than in comparable JET-C plasmas as taken by the density normalised intensity of CIII (97.7nm) line (Fig.2). There is no evidence of any significant increase in residual carbon in time, indicating that no damage of the W-coatings on CFC substrate in the divertor has occurred. Oxygen levels are also lower by roughly one order of magnitude with respect to JET-C with non-optimal wall conditions (although only marginally lower than in JET C-wall plasmas with well conditioned wall and following Be evaporations). This large reduction of residual impurity levels is similar to that found earlier by AUG when going from a all-C to a boronised [4] all-W wall. The line averaged Z eff decreases from ~2 (JET-C) to 1.2 (JET-ILW) for similar values of density and heating power. The lower residual carbon and oxygen level in JET-ILW is thought to be mainly due to gettering of carbon and oxygen by beryllium [5]. Specific effort has been devoted to investigate the impact to the operational space due to W core accumulation [6] and surface melting [7]. Beryllium erosion can shorten component lifetimes, contribute to tritium retention by re-deposition [8] and cause significant sputtering of tungsten. Tungsten sputtering has been studied in Land H-mode discharges. It is found that for the present range of temperatures and impurity content at JET most of the W sputtering in L-mode can be attributed to low Z impurities, more specifically Be ions (Fig.3). Experiments in L-mode have been performed to compare the impurity content under neutral beam (NBI) and Ion Cyclotron Resoance Frequency (ICRF) heating. As shown in Fig.4, the bulk radiation, defined as power radiated from inside the separatrix, is higher with ICRF [9] although significant electron heating is obtained and the increase in plasma energy is similar to C-wall values. It was estimated that around 80% of the radiation comes from W and 20% by Nickel with sources from the divertor entrance and main chamber [10] [11]. The cause for this increased radiation remains the subject of ongoing investigation [9]. It could be due to the generation of fast Be ions in front of the antenna following the field lines to the divertor and giving rise to enhanced W sputtering. In H-mode plasmas, measurements of intra and inter ELM radiation from WI lines [12] indicate that ELM events dominate the sputtering of W (Fig.5). Transient increases have been observed in total radiated power, probably associated with small particles of medium/high Z materials, mostly W, entering the plasma. Since the start of plasma operation with the ILW, the frequency of such events has first increased, with the progressive increase of the additional heating power to the plasma, and then decreased. These sudden influxes are not necessarily fatal for the plasma which often recovers from the increased radiation [13]. 2.2. Plasma Breakdown and current rumP-uP The strong decrease of carbon content in the machine with the ILW has lead to a significant reduction

We present a detailed model describing the effects of wire corrugation on the trapping potential experienced by a cloud of atoms above a current carrying micro wire. We calculate the distortion of the current distribution due to corrugation and then derive the corresponding roughness in the magnetic field above the wire. Scaling laws are derived for the roughness as a function of height above a ribbon shaped wire. We also present experimental data on micro wire traps using cold atoms which complement some previously published measurements [11] and which demonstrate that wire corrugation can satisfactorily explain our observations of atom cloud fragmentation above electroplated gold wires. Finally, we present measurements of the corrugation of new wires fabricated by electron beam lithography and evaporation of gold. These wires appear to be substantially smoother than electroplated wires.

The photoabsorption cross-section of an ion immersed in a plasma is studied on the basis of the Thomas–Fermi approximation for the equilibrium electron distribution and Bloch's classical hydrodynamic model for collective motion of the electrons. The frequency-dependent cross-section scales with the nuclear charge, and depends strongly on the plasma density and temperature. An approximation of the frequency dependence is constructed with the aid of sum rules and Padé approximants.

Hartree-Fock equations for plasma atoms are proposed and used in the superconfiguration method of photoabsorption calculation. They involve statistical sums, taking into account integer shell occupation numbers and finite temperature effects. These sums are evaluated using electron and hole counting. Their use is also shown to be relevant to the treatment of orbital relaxation in the final states of optical transitions.

Thin film technology for device applications are based on material structures created by thin-film deposition and characterization [1]. In recent time, there are growing demands for more efficient solar cell technology and also electronic devices that could operate at high power levels. Suitable thin films for these applications require wide band gap, high optical conductivity, high transparency and stability at higher temperature [2]. The numerous varieties of electronic, optical and solid state properties of metal oxides make them suitable materials for basic research that results in invention of novel systems and improvement on the exiting. Oxides have a wide range of properties from wide band-gap insulators, metallic to superconducting. Tin oxide belongs to a class of materials called Transparent Conducting Oxides (TCO), constituting an important component for optoelectronic applications [3]. Tin oxide thin films have some useful applications in visible light and infrared light....

Information Center is to provide broadest dissemination possiof information contained in DOE's Research and Development Reports to business, industry, the academic community, and federal, state and local governments. Although a small portion of this report is not reproducible, it is being made available to expedite the availability of information on the research discussed herein.

This paper reviews the status of methods used to analyze local transport of particles, energy, and angular momentum in plasmas contained in toroidal fusion devices. The standard technique at present is based on determination of particle, energy, and momentum fluxes through analysis based on measured profiles of density, temperature and angular rotation speed and on calculation of all sources of particles, energy, and momentum. Recent experiments have also been done using perturbations of local density, temperature, or angular rotation speed caused by modulating the input sources. The local transport information is then extracted from the time history of the perturbations. These two techniques are contrasted and the strengths of each are discussed in this paper. Recommendations for further work needed to make progress in understanding transport are also given.

The experimental results of electrostatic probe measurements on the LBL 10 ampere ion source are presented. Data is obtained via a pulsed acquisition system which digitally records a probe charac teristic and its firs;, and second derivatives. The latter are shown to be proportional to the projected electron energy distribution function, and the isotropic electron energy distribution function, respectively. System performance for distribution function measurement is compared to the established technique of harmonic analysis. A complete analysis of the data acquisition system and its experimental accuracy is presented. Experimental measurements include the electron em ray distribution function f (r,e), and variation of general plasma properties (bulk electron temperature, plasma potential, plasma density, saturated ion current, arc discharge current and a.iode potential) as a function of source spatial position, arc power and inpu*-gas flow. The results are compared to previous experimental work and prevailing theories where feasible.

Recently, Barger et al. computed energy losses into Kaluza Klein modes from astrophysical plasmas in the approximation of zero density for the plasmas. We extend their work by considering the effects of finite density for two plasmon processes. Our results show that, for fixed temperature, the energy loss rate per cm 3 is constant up to some critical density and then falls exponentially. This is true for transverse and longitudinal plasmons in both the direct and crossed channels over a wide range of temperature and density. A difficulty in deriving the appropriate covariant interaction energy at finite density and temperature is addressed. We find that, for the cases considered by Barger et al., the zero density approximation and the neglect of other plasmon processes is justified to better than an order of magnitude.

Future in situ space plasma investigations will likely involve spatially distributed observatories comprised of multiple spacecraft, beyond the four and five spacecraft configurations currently in operation. Inferring the magnetic field structure across the observatory, and not simply at the observation points, is a necessary step towards characterizing fundamental plasma processes using these unique multi-point, multi-scale data sets. We propose improvements upon the classic first-order reconstruction method, as well as a second-order method, utilizing magnetometer measurements from a realistic nine-spacecraft observatory. The improved first-order method, which averages over select ensembles of four spacecraft, reconstructs the magnetic field associated with simple current sheets and numerical simulations of turbulence accurately over larger volumes compared to second-order methods or first-order methods using a single regular tetrahedron. Using this averaging method on data sets w...

By applying mass spectrometry techniques, we carried out measurements of ionic mass spectrum and their energy distribution in order to investigate an atmospheric argon discharge by using a surfatron surface-wave device. The mass and energy distribution measurements were performed with fixed flow rate (2.5 SLM) of pure argon gas (99,999%) and different Ar-O 2 gas mixture compositions (99-1, 98-2 and 97-3). The mass spectra and energy distributions were recorded for Ar + , O + , O + 2 , N + and N 2 +. The axial distribution profiles of ionic mass and their energy were obtained for different experimental conditions as a function of the plasma length. The results showed that the peak of the positive ion energy distributions shifted to higher energies and also that the distribution width increased as the distance between the sampling orifice and the launcher gap was increased. It was also found that under certain experimental conditions the ion flux of atomic species were higher than the ion flux of their diatomic counterpart. The motivation of this study was to obtain a better understanding of a surface wave discharge in atmospheric pressure that may play a key role on new second generation biofuel technologies.

A review of nonneutral plasma science issues for heavy ion drivers is presented. The requirements on transverse and longitudinal focusing at the target lead to constraints on the 6D phase space. Mechanisms which act to prevent focusability, including emittance growth, space charge and instabilities are discussed. Experiments which have explored and validated our understanding of beam transport and focusability of space-charge dominated heavy ion beams are described.

A kinetic theory of the Debye sheath in the Tonks–Langmuir model of the plasma-wall transition layer with hot neutrals is presented. The plasma, consisting of Boltzmann-distributed electrons and singly charged ions, is in contact with an absorbing negative wall. Dependencies of electric-potential characteristics on neutrals temperature are investigated for the first time. The results can be generalized to other sheath models.

The energy problem refers to the generation, distribution, and consumption of energy, particularly in the context of sustainability, environmental impact, and meeting growing global demand.
In addition to the solutions offered by contemporary science, this paper also presents the solution to the energy problem offered by Nikola Tesla based on his ether technologies.

We study the patterns observed in the vicinity of a Faraday instability, in the limit of a very thin layer of viscous fluid. We numerically solve our previous model [N.O. Rojas et al., Phys. Rev. Lett. 104, 187801 (2010)] and compare our predictions to experiments. Our model captures quantitatively the threshold of instability. The direct simulation of our system permits us to predict the patterns observed in experiments.

We study the formation of slow-mode shocks in collisionless magnetic reconnection by using one-and two-dimensional collisionless MHD codes based on the double adiabatic approximation and the Landau closure model. We bridge the gap between the Petschek-type MHD reconnection model accompanied by a pair of slow shocks and the observational evidence of the rare occasion of in-situ slow shock observations. Our results showed that once magnetic reconnection takes place, a firehose-sense (p || > p ⊥) pressure anisotropy arises in the downstream region, and the generated slow shocks are quite weak comparing with those in an isotropic MHD. In spite of the weakness of the shocks, however, the resultant reconnection rate is 10 − 30% higher than that in an isotropic case. This result implies that the slow shock does not necessarily play an important role in the energy conversion in the reconnection system, and is consistent with the satellite observation in the Earth's magnetosphere.

The world was nothing in an infinity of space and time. Somewhere in this space of nothing, something dramatic happened: An energy discharge occurred. We call it BIG BANG. Only energy was created. Nothing more. Energy is force multiplied by distance divided by time. Everything in the world, therefore, consists of the three basic elements: force, distance (length), and time. There is no other basic element. (Everything in the world consists of energy). What was created in the BIG BANG was, therefore, necessarily a mass in motion. This mass-which we call ether mass-must be similar to a homogeneous gas. But it can not consist of atoms. Instead, ether-mass consists of force fields. Changing the motion of an ether mass = force. Movements = distance divided by time. The created energy was surrounded by nothing. It can, therefore, not disappear but must keep an eternally unchanged amount. The ether mass, which is part of this energy, must, therefore, also be eternal. It can not be éaten up ́ by the surroundings, which consist of nothing. It must, therefore, have a surface membrane towards volumes that contain nothing. (The explanation is: A force can only exist when it collides with another force that acts in the opposite direction. And the magnitude of the force becomes equal to the weakest force that then arises. Therefore, no force has a direction outwards towards nothing. In the boundary surface between ether-mass and nothing, there are then only forces that lie in this plane. They form the mentioned surface membrane). But ether-mass can expand outwards into the surrounding void. (When that happens, it will always be as a result of force influences from inside the ether mass. There, forces with the greatest force potential (most energy) push opposing forces backward). Then, the powerful movements of the ether mass from the BIG BANG will become less powerful and correspondingly greater in extent. After a very long time, these movements of the ether mass have become an enduring basic vibration in the ether ́ where the pressure variations are very rapid. (A homogeneous ether mass with very rapid pressure variations is not recorded by humans or their equipment). With the BIG BANG, the world became ¨materialized¨. Then, the concept of sizes arose. The basic elements made sense with scales for these sizes. The scales gave the BIG BANG its size in the space of nothingness. The scales are, therefore, the ¨keys¨ for the creation of the world. They gave BIG BANG its power, and it became violently large.

The Budker Institute of N u d m Physics March 1993 ~iS'lRlBUTlfJN OF THIS DOCUMENT IS UNLIMITUJ \ DISCLAIMER This report was .prepared as a n account of work sponsored by an agency of t h e United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, make any warranty, express or implied, or assumes a n y legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by t h e United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. DISCLAIMER Portions of this document may be illegible in electronic image products. Images are produced from the best available original document.- .

The variational principle of barotropic Eulerian fluid dynamics is known to be quite cumbersome containing as much as eleven independent functions. This is much more than the the four functions (density and velocity) appearing in the Eulerian equations of motion. This fact may have discouraged applications of the variational method. In this paper a four function Eulerian variational principle is suggested and the implications are discussed briefly.

Significant advances in microwave and millimeter wave technology over the past decade have enabled the development of a new generation of imaging diagnostics for current and envisioned magnetic fusion devices. Prominent among these are revolutionary microwave electron cyclotron emission imaging (ECEI), microwave phase imaging interferometers, imaging microwave scattering and microwave imaging reflectometer (MIR) systems for imaging T e and n e fluctuations (both turbulent and coherent) and profiles (including transport barriers) on toroidal devices such as tokamaks, spherical tori and stellarators. The diagnostic technology is reviewed, and typical diagnostic systems are analyzed. Representative experimental results obtained with these novel diagnostic systems are also presented.

This work is devoted to the thermodynamics of high-temperature dense hydrogen plasmas in the pressure region between 10 −1 and 10 2 Mbar. In particular we present for this region results of extensive calculations based on a recently developed path integral Monte Carlo scheme (direct PIMC). This method allows for a correct treatment of the thermodynamic properties of hot dense Coulomb systems. Calculations were performed in a broad region of the nonideality parameter Γ 3 and degeneracy parameter n e Λ 3 10. We give a comparison with a few available results from other path integral calculations (restricted PIMC) and with analytical calculations based on Padé approximations for strongly ionized plasmas. Good agreement between the results obtained from the three independent methods is found.

The semiclassical dynamics of a charged particle moving in a two-component plasma is considered using a corrected Kelbg pseudopotential. We employ the classical Nevanlinna-type theory of frequency moments to determine the velocity and force autocorrelation functions. The constructed expressions preserve the exact short and long-time behavior of the autocorrelators. The short-time behavior is characterized by two parameters which are expressable through the plasma static correlation functions. The long-time behavior is determined by the self-diffusion coefficient. The theoretical predictions are compared with the results of semiclassical molecular dynamics simulation.

An integrated modeling framework for investigating the application of solid boron (B) powder injection for real-time surface conditioning of plasma-facing components (PFCs) in tokamak environments is presented. Utilizing the DIII-D impurity powder dropper (IPD) setup, this study simulates B powder injection scenarios ranging from milligrams to tens of milligrams per second, corresponding to boron flux rates of 10 20 − 10 21 B/s in standard L-mode conditions. The comprehensive modeling approach combines EMC3-EIRENE for simulating the deuterium plasma background and the Dust Injection Simulator (DIS) for the ablation and transport of the boron powder particles. EMC3 trace impurity fluid modeling results show substantial boron transport to the inboard lower divertor, predominantly influenced by the main ion plasma flow. The dependency on powder particle size (5-250 µm) was found to be insignificant for the scenario considered. The effects of erosion and redeposition were considered to reconcile the discrepancies with experimental observations, which saw substantial deposition on the outer divertor plasma-facing components. For this purpose, the WallDYN3D code was updated to include boron sources within the plasma domain and integrated into the modeling framework. The mixed-material migration modeling shows evolving boron deposition patterns, suggesting the formation of mixed B-C layers or predominantly B coverage depending on the powder mass flow rate. While the modeling outcomes at lower B injection rates tend to align with DIII-D experimental observations, the prediction of near-pure boron layers at higher rates has yet to be experimentally verified in the carbon environment of the DIII-D tokamak. The extensive reach of boron layers found in the modeling suggests the need for modeling that encompasses the entire wall geometry for more accurate experimental correlations. This integrated approach sets a precedent for analyzing and applying real-time in-situ boron coating techniques in advanced tokamak scenarios, potentially extendable to ITER.

Submitted for the GEC09 Meeting of The American Physical Society How valid is the concept of a bi-Maxwellian distribution? N.S. BRAITHWAITE, R.N. FRANKLIN, The Open University-The sheath of a plasma with two distinct negative species was examined by Braithwaite and Allen (1988). There is no doubt of its validity to describe the situation in electronegative plasmas at low pressures when the species are electrons and negative ions, and much of the understanding of such plasmas has resulted. Though it may be convenient to describe the electron energy distribution in electropositive plasmas as if there are two distinct species, one needs to be careful in deriving such things as a modified Bohm criterion. In most situations there is but one distribution and one cannot distinguish "red" and "blue" electrons. The electrons move between different parts of the distribution by a process of "diffusion" well described by Tsendin (2009). Thus unless different parts of the total electron distribution clearly do not interact, results obtained by assuming two independent populations with different densities and temperatures lack validity.

Recent aging studies performed on dilute and concentrated metal tritides are reviewed. Also, new results concerning property changes in metal tritides as a function of aging time are included. We mainly report on TEM studies of aged tritides, the swelling behavior, hardness measurements, selected mechanical properties, acoustic emission and tritium diffusion experiments. Models of the microstrueture of aged tritides are also reported. Density measurements on tritides are discussed.

Small quasi-two-dimensional (2D) dust clusters consisting of three to eleven particles are formed in an argon plasma under varying rf power. Their normal modes are investigated through their mode spectra obtained from tracking the particles' thermal motion. Detailed coupling patterns between their horizontal and vertical modes are detected for particle numbers up to seven and discrete instabilities are found for dust clusters with particle number ≥ 9, as predicted in previous theory on ion-flow induced mode coupling in small clusters. The instabilities are proven to be induced by resonance between coupled horizontal and vertical normal modes.

High-power debris-free vacuum ultraviolet (VUV) light sources have applications in several scientific and engineering areas, such as high volume manufacturing lithography and inspection tools in the semiconductor industry, as well as other applications in material processing and photochemistry. For the past decades, the semiconductor industry has been driven by what is called "Moore's Law". The entire semiconductor industry relies on this rule, which requires chip makers to pack transistors more tightly with every new generation of chips, shrinking the size of transistors. The ability to solve roadmap challenges is, at least partly, proportional to our ability to measure them. The focus of this thesis is on imaging transient VUV laser plasma sources with specialized reflective imaging optics for metrology applications. The plasma dynamics in novel laser-based Zinc and Tin plasma sources will be discussed. The Schwarzschild optical system was installed to investigate the time evolution of the plasma size in the VUV region at wavelengths of 172 nm and 194 nm. The outcomes are valuable for interpreting the dynamics of low-temperature plasma and to optimize laser-based VUV light sources. iv ACKNOWLEDGMENTS I would wish to gratefully thank Dr. Martin Richardson for giving me the opportunity and support, and encouragement to perform this project. Likewise, I thank the committee members, Dr. Patrick Likamwa and Dr. Jim Moharam for being my committee members and spending time on my thesis. I desire to thank EUV team, Dr. Majid Masnavi, Dr. Homaira Parchamy, John Szilagyi for discussions and support, and all LPL members, especially, Nathan Bodnar, Joshua Bradford, Cheonha Jeon for help. Also, thank Richard Zotti for teaching and helping me how to construct my system in a machine shop. At last, not least, I like to acknowledge my parents and kin. v

A simple model is investigated according to which the deformation of the vacuum corresponding to the localization of a particle is described by particular solutions of an appropriately rescaled Wheeler-De Witt (WdW) equation. The role of the usual gravitational constant is in fact played by a different constant, defined by a suitable geometric representation of the Higgs mechanism. The particle is then described in terms of a micro-universe of size 10-13 cm, without contradiction with the point-like nature of the charges. Different definitions of the temporal variable give rise to different solutions which, suitably connected, lead to a temporal evolution of the particle that is wider than that normally contemplated. For example, it is possible to dynamically describe quantum jumps and obtain a decoherence mechanism compatible with the phenomenon of flavor mixing. Some cosmological consequences and the possibilities of experimental verification are briefly discussed.

We consider the interaction of subpicosecond relativistically strong short laser pulses with an underdense cold unmagnetized electron plasma. It is shown that the strong plasma inhomogeneity caused by laser pulses results in the generation of a low frequency (quasistatic) magnetic field. Since the electron density distribution is determined completely by the pump wave intensity, the generated magnetic field is negligibly small for nonrelativistic laser pulses but increases rapidly in the ultrarelativistic case. Due to the possibility of electron cavitation (complete expulsion of electrons from the central region) for narrow and intense beams, the increase in the generated magnetic field slows down as the beam intensity is increased. The structure of the magnetic field closely resembles that of the field produced by a solenoid; the field is maximum and uniform in the cavitation region, then it falls, changes polarity and vanishes. In extremely dense plasmas, highly intense laser pulses in the self-channeling regime can generate magnetic fields-100MG and greater.

It is shown that pair plasmas, through the new focusing–defocusing nonlinearity generated by an ‘asymmetry’ in initial temperatures of constituent species, can support multidimensional, stable, large-amplitude light bullets as well as bullets carrying vortices, i.e. spinning bullets.

I have studied every discipline with an open mind. I have faced years of near mental collapse, perceived hardships to ow end, and have emerged with the answers I sought.

I bring you all the keys to everything. To the Faith Equation. To prove once and for all, that we exist as vibrations within a frictionless plasma medium.

Plasma is referred to as the 4th state of matter, because we understood it last. Plasma is the only state of matter, and if you take the 4 minutes to read this with an open mind, you too will come to understand this place.

High-order harmonics from relativistic electron spikes [1, 2] are generated by multi-terawatt femtosecond lasers focused onto gas jet targets up to irradiances exceeding 10 18 W/cm 2. Possible applications of these harmonics range from plasma diagnostics to compact bright attosecond x-ray sources. These applications require stability and well understood generation processes. Here we present statistical analysis of the harmonic generation employing a dataset from a large number of shots with the J-KAREN laser [3] with the emphasis on the reproducibility, stability, and spectral shape properties. The latter include analysis of base harmonic frequencies with a typical separation of ~ eV and relatively slow spectral modulations with a period up to a few tens of eV, which may give a hint to the temporal structure of the XUV radiation.

When an intense, plane-polarized, laser pulse interacts with a plasma, the relativistic nonlinearities fP induce a third harmonic polarization. A phase-locked growth of a third harmonic wave can tak; place, but the difference between the nonlinear dispersion of the pump and driven waves leads to a rapid li

A new nonlinear Raman instability in underdense plasma is investigated theoretically. Unlike the usual linear Raman instabilities which grow exponentially in time, this instability takes a finite amount of time to diverge. T h e explosion time t, depends on the initial level of the perturbation. A general set of equations for spatietemporal evolution of the forward nonlinear Raman scattering is derived and its temporal evolution is studied in detail. This new instability results in the generation of forward Raman radiation shifted by half the plasma frequency for laser intensities of order or exceeding 10'8W/cm2, something that has been recently observed (Astorre Modena, private communication, 1995).

Capacitive discharges have classically been modeled in the electrostatic approximation. However, electromagnetic effects become significant if the excitation wavelength and the plasma skin depth are not infinite. An electromagnetic model valid in the entire range of and of practical interest is solved. We find that the plasma may either be sustained by the usual capacitive E field or by an inductive H field, and that the discharge experiences E to H transitions as the voltage between the electrodes is raised.