A5030081189- Atomic and Molecular Physics
- Laser-induced spectroscopy and plasma
- Magnetic confinement fusion research
- Laser-Matter Interactions and Applications
- Laser-Plasma Interactions and Diagnostics
- Laser Design and Applications
- Plasma Diagnostics and Applications
- X-ray Spectroscopy and Fluorescence Analysis
- Particle accelerators and beam dynamics
- Advanced X-ray Imaging Techniques
- Ionosphere and magnetosphere dynamics
- Solid State Laser Technologies
- Mass Spectrometry Techniques and Applications
- Fusion materials and technologies
- Quantum optics and atomic interactions
- Dust and Plasma Wave Phenomena
- Advanced Chemical Physics Studies
- Nuclear Physics and Applications
- Gas Dynamics and Kinetic Theory
- Diamond and Carbon-based Materials Research
- Solar and Space Plasma Dynamics
- Adrenal and Paraganglionic Tumors
- Superconducting Materials and Applications
- Spectroscopy Techniques in Biomedical and Chemical Research
- Atomic and Subatomic Physics Research
Princeton University
2011-2021
Baylor University
2021
Texas A&M University
2020-2021
Bridge University
2021
Princeton Plasma Physics Laboratory
1989-2018
Cornea and Laser Eye Institute - Hersh Vision Group
2015
East China Normal University
2015
Cornell University
1995
Princeton Public Schools
1993
National Technical Information Service
1986-1991
An enhancement of \ensuremath{\sim}100 stimulated emission over spontaneous the C vi 182-A\r{} line (one-pass gain \ensuremath{\sim}6.5) was measured in a recombining, magnetically confined plasma column by two independent techniques involving intensity calibrated extreme xuv monochromators. Additional confirmation that due to has been obtained with soft x-ray mirror; 12% effective reflectivity mirror, 120% increase axial direction observed.
A high-resolution, time-resolving soft x-ray multichannel spectrometer (SOXMOS) that permits the simultaneous measurement of emission in two different spectral ranges has been developed and tested extensively for tokamak plasma diagnostics. The basic instrument is a interferometrically adjusted, extreme grazing incidence Schwob–Fraenkel duochromator. equipped with detectors are adjusted scan along Rowland circle. Each consists an MgF2 coated, funneled microchannel plate, associated phosphor...
In this review we concentrate our attention on X-ray laser research and development covering the so called soft region (down to ∼ 10 nm) ``water window'' 2.3 – 4.4 nm). We present of lasers (SXLs) their applications using primarily collisional recombination schemes. paths towards compact systems major achievements date. discuss conditions for both schemes reach region. discussion also another possible based photo-pumping, inner shell transitions in atoms ions ``Doppler Compression'' IR...
Soft x-ray lasing with a gain length $\mathrm{GL}\ensuremath{\approx}5.5$ was demonstrated in hydrogenlike Li III at 13.5 nm (2-1 transition) 5 mm long LiF microcapillary using 50 mJ, 250 fs UV laser beam 2 Hz repetition rate. The initial plasma created the 0.3 diameter by low power Nd/YAG laser. strongly nonlinear increase of line intensity increasing compared linear 11.4 (3-1 intensity.
The intensity of a subpicosecond laser pulse was amplified by factor up to 1000 using the Raman backscatter interaction in 2 mm long gas jet plasma. process amplification reached nonlinear regime, with exceeding that pump more than an order magnitude. Features unique regime such as gain saturation, bandwidth broadening, and shortening were observed. Simulation theory are qualitative agreement measurements.
Raman amplification of subpicosecond laser pulses up to 95 times is demonstrated at corresponding frequencies in a gas-jet plasma. The larger accompanied by broader bandwidth and shorter pulse duration. Theoretical simulations show qualitative agreement with the measurements, effects plasma conditions intensities are discussed.
Toroidal plasma rotation, generated by toroidally unbalanced neutral-beam injection into the Princeton Large Torus, has been measured Doppler shifts of several atomic spectral lines. These measurements produce time evolution and spatial distribution rotation from which a momentum confinement time, comparable to ion energy is deduced.
Toroidal plasma rotation in the Princeton Large Torus, PLT, has been measured for various and neutral-beam injection conditions. Measurements of rotational velocities were made from Doppler shifts appropriate spectra lines include data both hydrogen deuterium beams co- counter-injection at several electron densities. Without injection, a small but consistent toroidal exists direction opposite to current (counter-direction) centre parallel (co-direction) periphery. Using these absence density...
Experimental results from high-power neutral-beam-injection experiments on the Princeton Large Torus tokamak are reported. At highest beam powers (2.4 MW) and lowest plasma densities [${n}_{e}(0)=5\ifmmode\times\else\texttimes\fi{}{10}^{13}$ ${\mathrm{cm}}^{\ensuremath{-}3}$], ion temperatures of 6.5 keV achieved. The collisionality ${{\ensuremath{\nu}}_{i}}^{*}$ drops below 0.1 over much radial profile. Electron heating $\frac{\ensuremath{\Delta}{T}_{e}}{{T}_{e}}\ensuremath{\approx}50%$ has...
Toroidal and poloidal rotation has been measured in the Poloidal Divertor Experiment (PDX) tokamak Ohmic neutral-beam heated plasmas a variety of discharge conditions both circular diverted configurations. Rotation velocities were deduced from Doppler shifts magnetic dipole (M1) lines optically allowed transitions visible UV regions, Kα emission, also an array pickup loops. toroidal Ohmically discharges usually less than 3 × 105 cm·s−1. Near plasma edge, velocity varies with angle before...
The development of noninductive current drive is great importance in establishing the tokamak as a long-pulse or steady-state fusion reactor. Lower hybrid waves, carrying 200 kW power at 800 MHz, have been launched into Princeton Large Torus to initiate and discharge level excess 100 kA.
Wavelength measurements of n=3 to n=2 transitions in neonlike ${\mathrm{Xe}}^{44+}$, ${\mathrm{La}}^{47+}$, ${\mathrm{Nd}}^{50+}$, and ${\mathrm{Eu}}^{53+}$ have been made using a high-resolution Bragg-crystal spectrometer on the Princeton Large Torus tokamak. The cover wavelength regions 2.00--3.00 A\r{} include electric dipole magnetic quadrupole transitions. measured wavelengths are compared energy levels obtained from multiconfigurational Dirac-Fock calculation. Systematic differences...
A spectrum line in the Princeton Large Torus (PLT) tokamak discharges, with wave-length measured as 2665.1 \ifmmode\pm\else\textpm\fi{} 0.3 \AA{}, has been identified $2{s}^{2}2{p}^{3}^{2}D_{\frac{5}{2}}\ensuremath{\rightarrow}^{2}D_{\frac{3}{2}}$ magnetic dipole transition Fe xx ground configuration. variety of localized spectroscopic diagnostics, e.g., ion temperature and density distribution measurements high-temperature interior plasma, are feasible by means forbidden lines this type....
Low-Z impurity transport in tokamaks was simulated with a one-dimensional model including both neoclassical and anomalous transports. The fluxes are due to collisions between the background plasma ions as well various ionization states. evaluation of takes into account different collisionality regimes ions. A limiter scrape-off is used define boundary condition for periphery. To spectroscopic measurements power radiated by lower states, included. sensitivities results uncertainties rate...
A number of spectrum lines highly ionized copper, nickel, iron, chromium, and germanium have been observed the corresponding transitions identified. The element under study is introduced into discharge Princeton Large Torus tokamak by means rapid ablation a laser pulse. ionization state generally distinguishable from time behavior emitted light. New identifications are based on predicted wavelengths (from isoelectronic extrapolations other data) approximate expected intensities. All pertain...
Several spectrum lines from forbidden transitions in the ground configurations of highly ionized atoms have been observed discharges Princeton Large Torus tokamak. Such allow localized observations, high-temperature regions plasma, ion-temperatures, plasma motions, and spatial distributions ions. Measured absolute intensities compared with simultaneous observations ion resonance lines. Model calculations carried out order to deduce relative importance electron collisions radiative decays...
The emerging technology of soft x-ray lasers has novel applications to microscopy, lithography, and other fields. This article describes the status laser research with aim bringing rapid developments in this field attention potential users disciplines. different techniques for generating a population inversion producing are reviewed. current near-term prospects described. It is expected that range will increase as their performance improves. Work aimed at increasing output power progressing...
The divergence of the C VI 182-\AA{} lasing line generated in a rapidly recombining, magnetically confined plasma column was measured with soft---x-ray spectrometers equipped multichannel detectors. In addition to measurements relative divergence, an absolute \ensuremath{\sim}9 mrad at magnetic field 20 kG and \ensuremath{\sim}5 35 or 50 obtained by direct scan axial radiation. Based on these data peak power \ensuremath{\sim}100 kW is obtained. Calculations spatial distribution gain were...
The enhancement of stimulated Raman backscattering (SRBS) amplification was demonstrated by introducing a plasma density gradient along the pump and seed interaction path novel double-pass design. energy transfer efficiency significantly improved to level 6.4%. pulse amplified factor more than 20 000 from input in 2mm long plasma, which also exceeded intensity 2 orders magnitude. This accompanied very effective compression, 500fsto90fs first pass measurements second down approximately 50fs,...
The idea of using a multi-Z (e.g., carbon, oxygen) thin plasma column as medium for soft x-ray lasing action is presented. A confined by strong magnetic field first heated CO2 laser, and then cools rapidly radiation losses. This leads to level population inversion hydrogen-like carbon or oxygen ions. Two computational models are One uses given electron temperature Te(t) evolutions. other calculated from an energy balance equation with laser beam power parameter. According calculations, total...
We present calculations of electron impact collision strengths and spontaneous radiative decay rates for neon-like krypton (Kr XXVII) the 2s22p6, 2s22p53s, 2s22p53p, 2s22p53d configurations. From these atomic data level populations as a function density were calculated at two temperatures (Te=1×107 K Te=3×107 K). The analysis shows that volume in which significant number ions are Kr XXVII degree ionization can produce gain transitions between 2s22p53s 2s22p53p At an 1×1019 cm−3 plasma length...
We experimentally demonstrated amplification of ultrashort laser pulses (200 fs pulses) in microcapillary plasmas by a counterpropagating pumping beam. Energy as large factor 5 was observed. Importantly, nonlinear pump depletion regime must have been accessed, since the parameters support not only pulse, but an absolutely growing instability if is depleted. Further indication accessing indicated relative insensitivity to initial pulse energy.
Ion heating by irradiation of rf fields in the ion-cyclotron range frequencies is investigated using several diagnostic techniques. It shown that substantial bulk ions can be achieved this method.