The materials contained in this group are either posters that I presented at conferences, or publications from physics journals. Bear in mind that the posters are typically written with the intention of presenting them to an audience. As such, the poster by itself does not always provide a self-contained and complete description of its subject matter. This does not mean they are useless, just that they probably don't provide enough information for your inquiry.
DocumentsDate added
Last updated on December 11, 2011.
Abstract:
A scintillator-based fast ion loss detector (FILD) measures the pitch and energy of energetic ions reaching the wall at approximately 45-degrees below the outer midplane. Losses are observed in connection with various instabilities, including Alfvén eigenmodes, energetic particle driven geodesic acoustic modes, and tearing modes. Orbit trajectory calculations based on FILD measurements allow for the identification of ion/mode interactions in phase space. These orbit calculations are part of the development of a synthetic FILD diagnostic that is validated against the well-understood case of neutral beam prompt losses in a specially designed DIII-D discharge. Results from the FILD across an array of plasma parameters will be presented, along with the initial design calculations and physics goals pertaining to a second FILD that will be installed near the outer midplane before the next experimental campaign.
Presented at the 52nd Annual Meeting of the APS Division of Plasma Physics, November 8 - 12, 2010 Chicago, IL
Convective beam ion losses due to Alfvén eigenmodes in DIII-D reversed-shear plasmas
04/21/2011
Hits: 129
D.C. Pace, R.K. Fisher, M. Garcia-Munoz, W.W. Heidbrink, and M.A. Van Zeeland, Plasma Phys. Control. Fusion 53 (2011) 062001.
Online: Journal Page for this Publication
Abstract:
Coherent losses of neutral beam ions are observed at frequencies corresponding to toroidal and reversed-shear Alfvén eigenmodes (RSAEs) in DIII-D. Reversed-shear profiles are created by injecting beam power during the plasma current ramp. Beam ion losses stemming from Alfvén eigenmode activity contribute to flattening of the energetic ion density profile in such discharges. This is the first observation of convective beam ion losses due to RSAEs. The energies and pitch angles of lost ions are measured and found to exist within a well-defined region of phase space. Loss flux signals decrease in time as current penetrates and Alfvén eigenmode activity becomes more core localized. Preliminary Monte Carlo simulations of energetic ion interactions with measured mode structures show the dominant loss mechanism is a transition from a counter-passing orbit to a trapped orbit that is lost to the wall.
This paper is published in the journal Plasma Physics and Controlled Fusion and is copyright ©2011 IAEA. The website for Plasma Physics and Controlled Fusion is,
http://www.iop.org/ej/ppcf.
Transport of energetic ions due to sawteeth, Alfvén eigenmodes and microturbulence
04/01/2011
Hits: 136
D.C. Pace, R.K. Fisher, M. García-Muñoz, W.W. Heidbrink, G.R. McKee, M. Murakami, C.M. Muscatello, R. Nazikian, J.M. Park, C.C. Petty, T.L. Rhodes, G.M. Staebler, M.A. Van Zeeland, R.E. Waltz, R.B. White, J.H. Yu, W. Zhang, and Y.B. Zhu, “Transport of Energetic Ions due to Sawteeth, Alfvén Eigenmodes, and Microturbulence,” Nucl. Fusion 51, 043012 (2011).
This paper summarizes recent results from the Energetic Particle Working Group at the DIII-D National Fusion Facility. The transport of energetic ions is studied under a variety of perturbation sources. These sources include sawtooth crashes, Alfvén eigenmodes, and microturbulence, which represent a wide range of length scales. As a summary, this paper includes references to many upcoming results from the DIII-D facility.
This paper is published in the journal Nuclear Fusion and is copyright ©2011 IAEA. The website for Nuclear Fusion is,
http://www.iop.org/ej/nf.
Transport of Energetic Ions due to Microturbulence, Sawteeth, and Alfvén Eigenmodes
This is an invited talk that covers our present understanding of energetic ion transport in tokamaks due to instabilities at various scales. Details concerning this presentation may be found here.
Citation: D.C. Pace, R.K. Fisher, M. García-Muñoz, D.S. Darrow, W.W. Heidbrink, C.M. Muscatello, R. Nazikian, M.A. Van Zeeland, and Y.B. Zhu, “Modeling the response of a fast ion loss detector using orbit tracing techniques in a neutral beam prompt-loss study on the DIII-D tokamak,&rdquo Rev. Sci. Instrum. 81, 10D305 (2010).
This paper describes an analytic model of neutral beam prompt losses in DIII-D. The ultimate goal of this treatment is to calculate expected prompt loss levels and subtract them from losses due to other mechanisms such as MHD instabilities.
A summary of the paper may be found here.
Required AIP Copyright Statement: Copyright (2010) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Review of Scientific Instruments 81, 10D305 (2010) and may be found at http://rsi.aip.org/resource/1/rsinak/v81/i10/p10D305_s1.
Observation of Energetic Ion Transport due to Microturbulence and Comparison with Gyrokinetic Simulations
This is an invited talk concerning enhanced transport of neutral beam injected fast ions due to plasma turbulence. A discussion of this talk and the conference may be found here.
This is the complete version of my thesis, as turned in to the UCLA Library. It is also available as a collection of web pages, beginning here.
This is the published version of a research paper discussed on this page. The following statements are required by the publisher.
Copyright (2008) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.
The following article appeared in Phys. Plasmas 15, 122304 (2008) and may be found at http://link.aip.org/link/?PHP/15/122304.
Exponential Frequency Spectrum and Lorentzian Pulses in Magnetized Plasmas
This is my presentation for the 50th Annual Meeting of the Division of Plasma Physics of the American Physical Society held in Dallas, TX November 17 - 21, 2008.
The abstract may be found at http://meetings.aps.org/Meeting/DPP08/Event/88562.
More information on this presentation and the conference may be found here
This is a paper published by our research group during my time in graduate school. The citation is:
D. C. Pace, M. Shi, J. E. Maggs, G. J. Morales, and T. A. Carter, “Exponential Frequency Spectrum in Magnetized Plasmas,” Phys. Rev. Lett. 101, 085001 (2008)
A more detailed page describing this file is here.
Citation: Citation: D. C. Pace, M. Shi, J. E. Maggs, G. J. Morales, and T. A. Carter, “Spontaneous Thermal Waves in a Magnetized Plasma,” Phys. Rev. Lett. 101, 035003 (2008)
This paper presents results on electron temperature oscillations that arise spontaneously in a narrow temperature filament. The experiment is performed in the LAPD Laboratory and serves as part of my thesis work.
A more detailed discussion page for this item may be found here.
Flows and Transport Driven by Electron Temperature Gradients
The discussion page for this file may be found here.
Plasma Flows and Electron Heat Transport Driven by a Filamentary Pressure Structure
The presentation from my candidacy exam.
This is a "web friendly" download featuring no multimedia or interactive elements. This means that it is not exactly the same presentation given at the exam.
The discussion page for this file may be found here.
Initial Observations from Electron Heat Transport Studies in the LAPD
An informal talk describing three months of work on electron heat transport. This was the first presentation I made with Keynote, and I took advantage of the "build in" features. This means that the pdf of the talk has some duplicate slides. These exist because in the talk they fade in from within one slide.
Study of Magnetohydrodynamic Surface Waves in Liquid Gallium
Investigation of Density Accumulation in the Electric Tokamak
Investigation of Density Accumulation in the Electric Tokamak
Determination of the Electric Tokamak Equilibrium Properties using 1D and 2D Measurements
Application of the Motional Stark Effect to Measure Plasma Parameters in Tokamaks