scholarly journals Theoretical plasma physics

2019 ◽  
Vol 85 (6) ◽  
Author(s):  
Allan N. Kaufman ◽  
Bruce I. Cohen
Keyword(s):  
Test Particle ◽  
Radiation Transport ◽  
Collision Operator ◽  
Dispersion Function ◽  
Particle Theory ◽  
Wave Interactions ◽  
Quasilinear Theory ◽  
Wave Emission ◽  
The University ◽  
Plasma Dispersion

These lecture notes were presented by Allan N. Kaufman in his graduate plasma theory course and a follow-on special topics course (Physics 242A, B, C and Physics 250 at the University of California Berkeley). The notes follow the order of the lectures. The equations and derivations are as Kaufman presented, but the text is a reconstruction of Kaufman’s discussion and commentary. The notes were transcribed by Bruce I. Cohen in 1971 and 1972, and word processed, edited and illustrations added by Cohen in 2017 and 2018. The series of lectures is divided into four major parts: (i) collisionless Vlasov plasmas (linear theory of waves and instabilities with and without an applied magnetic field, Vlasov–Poisson and Vlasov–Maxwell systems, Wentzel–Kramers–Brillouin–Jeffreys (WKBJ) eikonal theory of wave propagation); (ii) nonlinear Vlasov plasmas and miscellaneous topics (the plasma dispersion function, singular solutions of the Vlasov–Poisson system, pulse-response solutions for initial-value problems, Gardner’s stability theorem, gyroresonant effects, nonlinear waves, particle trapping in waves, quasilinear theory, nonlinear three-wave interactions); (iii) plasma collisional and discreteness phenomena (test-particle theory of dynamic friction and wave emission, classical resistivity, extension of test-particle theory to many-particle phenomena and the derivation of the Boltzmann and Lenard–Balescu equations, the Fokker–Planck collision operator, a general scattering theory, nonlinear Landau damping, radiation transport and Dupree’s theory of clumps); (iv) non-uniform plasmas (adiabatic invariance, guiding-centre drifts, hydromagnetic theory, introduction to drift-wave stability theory).

Expansions of the mildly relativistic dispersion function for nearly perpendicular electron cyclotron ray tracing

1999 ◽  
Vol 61 (1) ◽  
pp. 121-128 ◽  
Author(s):  
I. P. SHKAROFSKY
Keyword(s):  
Ray Tracing ◽  
Computer Programs ◽  
Higher Order ◽  
Electron Cyclotron ◽  
Dispersion Function ◽  
Relativistic Dispersion ◽  
Plasma Dispersion ◽  
Derivatives Of ◽  
Cyclotron Harmonic ◽  
Experienced Difficulty

To trace rays very close to the nth electron cyclotron harmonic, we need the mildly relativistic plasma dispersion function and its higher-order derivatives. Expressions for these functions have been obtained as an expansion for nearly perpendicular propagation in a region where computer programs have previously experienced difficulty in accuracy, namely when the magnitude of (c/vt)2 (ω−nωc)/ω is between 1 and 10. In this region, the large-argument expansions are not yet valid, but partial cancellations of terms occur. The expansion is expressed as a sum over derivatives of the ordinary dispersion function Z. New expressions are derived to relate higher-order derivatives of Z to Z itself in this region of concern in terms of a finite series.

Dose Minimization Game for Smartphones

2018 ◽  
Author(s):  
Nolan Stelter ◽  
Arnav Das ◽  
Zahra Hanifah ◽  
Rizwan Uddin
Keyword(s):  
Radiation Protection ◽  
Radiation Transport ◽  
Educational Game ◽  
Virtual Model ◽  
Radiation Fields ◽  
Radiation Sources ◽  
Recent Developments ◽  
Time Distance ◽  
Important Time ◽  
The University

Due to misconceptions surrounding radiation and nuclear energy, educating the general public about basic radiation concepts has become increasingly important. The Virtual Education and Research Laboratory (VERL) at the University of Illinois at Urbana-Champaign (UIUC) has developed a 3D, virtual, interactive game that conveys the physics of radiation and principles of radiation protection to the player. The model is a scavenger hunt style game that takes place in a virtual model of a TRIGA research reactor. Several virtual radiation sources are placed in the 3D virtual model of the TRIGA facility. Radiation drops away from the radiation source. The effect of shielding can also be incorporated in modeling the radiation transport, leading to realistic radiation fields. The user’s goal is to find and collect (virtual) objects placed in this facility while minimizing the dose received in doing so. The player is meant to learn about time, distance, and shielding — key concepts in radiation protection. The start screen displays the radiation field in the form of a colored coded floor, as well as the location of the desired objects. With the given information, the player is encouraged to plan the route to collect the items and minimize exposure. By repeatedly playing the game, the player becomes familiar with the layout of the facility, and of the location of the radiation sources. This educational game is a useful teaching tool. Those unfamiliar with radiation protection concepts are able to understand how important time, distance, and shielding are in minimizing dosage. Additionally, this game proves to be a useful engagement and outreach tool. Upon completion of the game, the user is shown the score, the dose received, as well as a list of dose received in well-known instances such as eating a banana or in getting an x-ray at the dentist’s office. The dose minimization game developed earlier for computers has now been developed for use as a game-app for cell phones. These recent developments allow for wider outreach, further increasing the use of the model as an outreach and educational tool.

Plasma dispersion function for a Fermi–Dirac distribution

2010 ◽  
Vol 17 (12) ◽  
pp. 122103 ◽  
Author(s):  
D. B. Melrose ◽  
A. Mushtaq
Keyword(s):  
Dispersion Function ◽  
Dirac Distribution ◽  
Plasma Dispersion

scholarly journals Electron velocity distribution function in a plasma with temperature gradient and in the presence of suprathermal electrons: application to incoherent-scatter plasma lines

1998 ◽  
Vol 16 (10) ◽  
pp. 1226-1240 ◽  
Author(s):  
P. Guio ◽  
J. Lilensten ◽  
W. Kofman ◽  
N. Bjørnå
Keyword(s):  
Distribution Function ◽  
Temperature Gradient ◽  
Velocity Distribution ◽  
Velocity Distribution Function ◽  
Electron Velocity ◽  
Dispersion Function ◽  
Electron Velocity Distribution ◽  
Incoherent Scatter ◽  
Suprathermal Electrons ◽  
Plasma Dispersion

Abstract. The plasma dispersion function and the reduced velocity distribution function are calculated numerically for any arbitrary velocity distribution function with cylindrical symmetry along the magnetic field. The electron velocity distribution is separated into two distributions representing the distribution of the ambient electrons and the suprathermal electrons. The velocity distribution function of the ambient electrons is modelled by a near-Maxwellian distribution function in presence of a temperature gradient and a potential electric field. The velocity distribution function of the suprathermal electrons is derived from a numerical model of the angular energy flux spectrum obtained by solving the transport equation of electrons. The numerical method used to calculate the plasma dispersion function and the reduced velocity distribution is described. The numerical code is used with simulated data to evaluate the Doppler frequency asymmetry between the up- and downshifted plasma lines of the incoherent-scatter plasma lines at different wave vectors. It is shown that the observed Doppler asymmetry is more dependent on deviation from the Maxwellian through the thermal part for high-frequency radars, while for low-frequency radars the Doppler asymmetry depends more on the presence of a suprathermal population. It is also seen that the full evaluation of the plasma dispersion function gives larger Doppler asymmetry than the heat flow approximation for Langmuir waves with phase velocity about three to six times the mean thermal velocity. For such waves the moment expansion of the dispersion function is not fully valid and the full calculation of the dispersion function is needed.Key words. Non-Maxwellian electron velocity distribution · Incoherent scatter plasma lines · EISCAT · Dielectric response function

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