Plasma and Beam Physics Commons^™

Magnetic Field Perturbation Of Plasma Striations, Aidan Miller

Summer Community of Scholars Posters (RCEU and HCR Combined Programs)

No abstract provided.

Stellarator Optimization With Poloidal Field Coils, Haley Wilson, Andrew Ware, Aaron Bader, Chris Hegna

Undergraduate Theses, Professional Papers, and Capstone Artifacts

Stellarators are devices that use magnetic fields to optimize the conditions needed for plasmas to undergo fusion. Unlike tokamaks, stellarators do not rely on a plasma current but can produce a helical magnetic field using only external coils. In a stellarator, the coils surrounding the plasma are called modular coils and those that follow the plasma are called poloidal field coils. Modular coils can be difficult to build if they are too complex. An effort is underway to develop coil conditions that meet both physics and engineering constraints. The FOCUS code was developed to flexibly optimize stellarator coil configurations [C. …

Design Of A 10 Mev Beamline At The Upgraded Injector Test Facility For E-Beam Irradiation, Xi Li, Helmut Baumgart, Gianluigi Ciovati, F.E. Hannon, S. Wang

Electrical & Computer Engineering Faculty Publications

Electron beam irradiation near 10 MeV is suitable for wastewater treatment. The Upgraded Injector Test Facility (UITF) at Jefferson Lab is a CW superconducting linear accelerator capable of providing an electron beam of energy up to 10 MeV and up to 100 µA current. This contribution presents the beam transport simulations for a beamline to be used for the irradiation of wastewater samples at the UITF. The simulations were done using the code General Particle Tracer with the goal of obtaining an 8 MeV electron beam of radius (3-σ) of ~2.4 cm. The achieved energy spread is ~74.5 keV. The …

Reflection And Transmission Of Electromagnetic Pulses At A Planar Dielectric Interface: Theory And Quantum Lattice Simulations, Abhay K. Ram, George Vahala, Linda Vahala, Min Soe

Electrical & Computer Engineering Faculty Publications

There is considerable interest in the application of quantum information science to advance computations in plasma physics. A particular point of curiosity is whether it is possible to take advantage of quantum computers to speed up numerical simulations relative to conventional computers. Many of the topics in fusion plasma physics are classical in nature. In order to implement them on quantum computers, it will require couching a classical problem in the language of quantum mechanics. Electromagnetic waves are routinely used in fusion experiments to heat a plasma or to generate currents in the plasma. The propagation of electromagnetic waves is …

Simulation Studies On The Interactions Of Electron Beam With Wastewater, X. Li, S. Wang, Helmut Baumgart, G. Ciovati, F. Hannon

Electrical & Computer Engineering Faculty Publications

The manufactured chemical pollutants, like 1,4 dioxane and PFAS (per- and polyfluroralkyl substances), found in the underground water and/or drinking water are challenging to be removed or biodegraded. Energetic electrons are capable of mediating and removing them. This paper utilizes FLUKA code to evaluate the beam-wastewater interaction effects with different energy, space and divergence distributions of the electron beam. With 8 MeV average energy, the electron beam exits from a 0.0127 cm thick titanium window, travels through a 4.3 cm distance air and a second 0.0127 cm thick stainless water container window with 2.43 cm radius, and finally is injected …

Construction And Testing Of The Terrestrial Rays Analysis And Detection (Tryad) Science Instrument, Jaiden Stark

Summer Community of Scholars Posters (RCEU and HCR Combined Programs)

No abstract provided.

Temporal Coherent Control Of Resonant Two-Photon Double Ionization Of The Hydrogen Molecule Via Doubly Excited States, Jean Marcel Ngoko Djiokap, Anthony F. Starace

Anthony F. Starace Publications

We use time-delayed, counter-rotating, circularly polarized few-cycle attosecond nonoverlapping pulses to study the temporal coherent control of the resonant process of two-photon double ionization (TPDI) of hydrogen molecule via doubly excited states for pulse propagation direction along ˆk either parallel or perpendicular to the molecular axis ˆR. For ˆk ‖ ˆR and a pulse carrier frequency of 36 eV resonantly populating the Q₂ 1∏ ⁺ _u (1) doubly excited state as well as other 1∏ ⁺ _u doubly excited states, we find that the indirect ionization pathway through these doubly excited states changes the character of the kinematical vortex-shaped …

Deeply Virtual Compton Scattering Off Helium Nuclei With Positron Beams, Sara Fucini, Mohammad Hattawy, Matteo Rinaldi, Segio Scopetta

Physics Faculty Publications

Positron initiated deeply virtual Compton scattering (DVCS) off ⁴He and ³He nuclei is described. The way the so-called d-term could be obtained from the real part of the relevant Compton form factor is summarized, and the importance and novelty of this measurement is discussed. The measurements addressed for ³He targets could be very useful even in a standard unpolarized target setup, measuring beam spin and beam charge asymmetries only. The unpolarized beam charge asymmetries for DVCS off ³He and ⁴He are also estimated, at JLab kinematics and, for ⁴He, also at a configuration typical …

A Proposed Beam-Beam Test Facility Combine, E. Nissen, Geoffrey Krafft, Jean Delayen

Physics Faculty Publications

The COmpact Machine for Beam-beam Interactions in Non-Equilibrium systems (COMBINE) is a proposed, dedicated, beam-beam test facility. The base design would make use of a pair of identical octagonal rings (2.5 meters per side) one rotated 180 degrees from the other, meeting at their common interaction point. These would be fed by an electron gun producing up to 125 keV electrons. The low energy will allow for beam-beam tune shifts commensurate with existing colliders, some linac-ring type systems, and will also allow for an exploration of the predicted effects of gear-changing, which would be performed using a variable pathlength scheme. …

Equations Of State For Warm Dense Carbon From Quantum Espresso, Derek J. Schauss

Theses and Dissertations

Warm dense plasma is the matter that exists, roughly, in the range of 10,000 to 10,000,000 Kelvin and has solid-like densities, typically between 0.1 and 10 grams per centimeter. Warm dense fluids like hydrogen, helium, and carbon are believed to make up the interiors of many planets, white dwarfs, and other stars in our universe. The existence of warm dense matter (WDM) on Earth, however, is very rare, as it can only be created with high-energy sources like a nuclear explosion. In such an event, theoretical and computational models that accurately predict the response of certain materials are thus very …

Evidence Of Increased Radio-Frequency Losses In Cavities From The Fundamental Power Coupler Cold Window, Frank Marhauser, Gianluigi Ciovati

Physics Faculty Publications

High radio-frequency (rf) losses measured for cavities in original Continuous Electron Beam Accelerator Facility (CEBAF) cryomodules, compared to the losses measured in single-cavity tests, have been a long-standing issue related to their performance. We summarize experimental evidence of increased rf losses in CEBAF cavities arising from the fundamental power coupler cold window and waveguide, respectively. Cryogenic rf tests were done on cavities tested in vertical cryostats as well as inside cryomodules in the accelerator tunnel. The cold window metallization losses were assessed by combining numerical results with measured data obtained with an existing cryogenic waveguide resonator setup. The results showed …

The Concept And Applications Of A Dual Energy Storage Ring, Bhawin Dital, Andrew Hutton, Geoffrey Krafft, Fanglei Lin, Vasiliy Morozov, Yuhong Zhang

Physics Faculty Publications

A dual energy electron storage ring configuration is initially proposed as an electron cooler to cool the ion beam in a collider. It consists of two energy loops, the electron beam in the high energy loop undergoes the synchrotron radiation damping to obtain the desired beam property and the beam in the low energy loop is for cooling of the ion beam. The two different energy loops are connected by an energy recovery linac. A lattice design of such a dual energy storage ring has been completed and beam stability conditions are established. We performed numerical simulations to demonstrate the …

Beam Spin Asymmetry In Semi-Inclusive Electroproduction Of Hadron Pairs, M. J. Amaryan, M. Hattawy, S. E. Kuhn, Y. Prok, J. Zhang, Z. W. Zhao, Et Al., Clas Collaboration

Physics Faculty Publications

A first measurement of the longitudinal beam spin asymmetry A_LU in the semi-inclusive electroproduction of pairs of charged pions is reported. A_LU is a higher-twist observable and offers the cleanest access to the nucleon twist-3 parton distribution function e(x). Data have been collected in the Hall-B at Jefferson Lab by impinging a 5.498-GeV electron beam on a liquid-hydrogen target, and reconstructing the scattered electron and the pion pair with the CLAS detector. One-dimensional projections of the A^sin_LU^ϕR moments are extracted for the kinematic variables of interest in the valence quark region. The …

Intense Monochromatic Photons Above 100 Kev From An Inverse Compton Source, Kirsten Deitrick, Georg H. Hoffstaetter, Carl Franck, Bruno D. Muratori, Peter H. Williams, Geoffrey A, Krafft, Balša Terzić, Joe Crone, Hywel Owen

Physics Faculty Publications

Quasimonochromatic x rays are difficult to produce above 100 keV, but have a number of uses in x-ray and nuclear science, particularly in the analysis of transuranic species. Inverse Compton scattering (ICS) is capable of fulfilling this need, producing photon beams with properties and energies well beyond the limits of typical synchrotron radiation facilities. We present the design and predicted output of such an ICS source at CBETA, a multiturn energy-recovery linac with a top energy of 150 MeV, which we anticipate producing x rays with energies above 400 keV and a collimated flux greater than 108 photons per second …

First Demonstration Of The Use Of Crab Cavities On Hadron Beams, R. Calaga, A. Alekou, F. Antoniou, R. B. Appleby, L. Arnaudon, K. Artoos, G. Arduini, V. Baglin, S. Barriere, H. Bartosik, P. Baudrenghien, I. Ben-Zvi, T. Bohl, A. Boucherie, O. S. Brüning, K. Brondzinski, A. Butterworth, G. Burt, O. Capatina, S. Calvo, T. Capelli, M. Carlà, F. Carra, L. R. Carver, A. Castilla-Loeza, E. Daly, L. Dassa, J. Delayen, S. U. De Silva, A. Dexter, M. Garlasche, F. Gerigk, L. Giordanino, D. Glenat, M. Guinchard, A. Harrison, E. Jensen, C. Julie, T. Jones, F. Killing, A. Krawczyk, T. Levens, R. Leuxe, B. Lindstrom, Z. Li, A. Macewen, A. Macpherson, P. Menendez, T. Mikkola, P. Minginette, J. Mitchell, E. Montesinos, G. Papotti, H. Park, C. Pasquino, S. Pattalwar, E. C. Pleite, T. Powers, B. Prochal, A. Ratti, L. Rossi, V. Rude, M. Therasse, R. Tomás, N. Stapely, I. Santillana, N. Shipman, J. Simonin, M. Sosin, J. Swieszek, N. Templeton, G. Vandoni, S. Verdú-Andrés, M. Wartak, C. Welsch, D. Wollman, Q. Wu, B. Xiao, E. Yamakawa, C. Zanoni, F. Zimmermann, A. Zwozniak

Physics Faculty Publications

Many future particle colliders require beam crabbing to recover geometric luminosity loss from the nonzero crossing angle at the interaction point (IP). A first demonstration experiment of crabbing with hadron beams was successfully carried out with high energy protons. This breakthrough result is fundamental to achieve the physics goals of the high luminosity LHC (HL-LHC) and the future circular collider (FCC). The expected peak luminosity gain (related to collision rate) is 65% for HL-LHC and even greater for the FCC. Novel beam physics experiments with proton beams in CERN’s Super Proton Synchrotron (SPS) were performed to demonstrate several critical aspects …

Transient Behavior Of Drift And Ionization In Atmospheric Pressure Nitrogen Discharge, S. K. Dhali

Electrical & Computer Engineering Faculty Publications

The fluid models are frequently used to describe a non-thermal plasma such as a streamer discharge. The required electron transport data and rate coefficients for the fluid model are parametrized using the local field approximation (LFA) in first order models and the local-mean-energy approximation (LMEA) in second order models. We performed Monte Carlo simulations in Nitrogen gas with step changes in the E/N (reduced electric field) to study the behavior of the transport properties in the transient phase. During the transient phase of the simulation, we extract the instantaneous electron mean energy, which is different from the steady state mean …

The Resistive Barrier Discharge: A Brief Review Of The Device And Its Biomedical Applications, Mounir Laroussi

Electrical & Computer Engineering Faculty Publications

This paper reviews the principles behind the design and operation of the resistive barrier discharge, a low temperature plasma source that operates at atmospheric pressure. One of the advantages of this plasma source is that it can be operated using either DC or AC high voltages. Plasma generated by the resistive barrier discharge has been used to efficiently inactivate pathogenic microorganisms and to destroy cancer cells. These biomedical applications of low temperature plasma are of great interest because in recent times bacteria developed increased resistance to antibiotics and because present cancer therapies often are accompanied by serious side effects. Low …

High Voltage Design And Evaluation Of Wien Filters For The Cebaf 200 Kev Injector Upgrade, Gabriel Palacios-Serrano, Helmut Baumgart, C. Hernández-García, P. Adderley, J. Benesch, D. Bullard, J. Grames, A. Hofler, D. Machie, M. Poelker, M. Stutzman, R. Suleiman

Electrical & Computer Engineering Faculty Publications

High-energy nuclear physics experiments at the Jefferson Lab Continuous Electron Beam Accelerator Facility (CEBAF) require highly spin-polarization electron beams, produced from strained super-lattice GaAs photocathodes, activated to negative electron affinity in a photogun operating at 130 kV dc. A pair of Wien filter spin rotators in the injector defines the orientation of the electron beam polarization at the end station target. An upgrade of the CEBAF injector to better support the upcoming MOLLER experiment requires increasing the electron beam energy to 200 keV, to reduce unwanted helicity correlated intensity and position systematics and provide precise control of the polarization orientation. …

Investigation Of Ions Accelerated Through Electrostatic Menisci In An Inductively Coupled Plasma, David D. Caron

Graduate Theses, Dissertations, and Problem Reports (ETD)

Plasmas are used in semiconductor fabrication as they allow for very precise control over processes such as etching and doping. This is achieved by extracting a beam of ions from the plasma to interact with and modify the surface of a silicon wafer. However, conventional fabrication methods are reaching spatial limitations as semiconductor features reach the atomic scale. Therefore, in order to better control the fabrication processes and facilitate the transition to three-dimensional architecture, a greater understanding of ion beam formation is needed. Ion beams are extracted at the boundary between the Debye sheath and an externally applied potential, which …

Single And Multi-Photon Laser Induced Fluorescence For Electric Thruster And Fusion Applications, Thomas E. Steinberger

Graduate Theses, Dissertations, and Problem Reports (ETD)

Single and Multi-photon Laser Induced Fluorescence for Electric Thruster and Fusion Applications

Thomas Edward Steinberger

Laser-based diagnostics are increasingly sought after to investigate a variety of plasmas due to their non-perturbative capabilities. Specifically, laser induced fluorescence (LIF) provides a highly localized and precise spectroscopic technique to measure absolute density, temperature, and bulk flow. In this work, LIF and two-photon absorption laser induced fluorescence (TALIF) are used to investigate electric propulsion and fusion-relevant plasmas, respectively. Ion velocity distribution functions (IVDF) of singly ionized atomic iodine (I II) are measured for the first time and lineshape characteristics are presented for the diagnosis …