Confinement of plasmas of arbitrary neutrality in a stellarator

Pedersen, T. S.; Boozer, Allen H.; Kremer, Jason P.; Lefrançois, Rémi

doi:10.1063/1.1645519

Cited by 6 publications

(5 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Furthermore, it has been suggested that the creation of electron-positron plasma in pulsars is essentially by energetic collisions between particles which are accelerated as a result of electric and magnetic fields in such systems (Sturrock 1971;Michel 1982Michel , 1991. On the other hand, the successful achievements for creation of the electron-positron plasmas in laboratories have been frequently reported in the scientific literatures (Gibson et al 1960;Gahn et al 2000;Pedersen et al 2003;Helander & Ward 2003;Amoretti et al 2003;Pedersen et al 2004;Chen et al 2009). In this regard, many authors have concentrated on the relativistic electron-positron plasmas (Berezhiani et al 1993;Verheest 1996;Gedalin et al 1998;Keston et al 2003;Muoz 2004;Laing & Diver 2006) because of its occurrence in astrophysics and encountering with positron as an antimatter in high-energy physics.…”

Section: Introductionmentioning

confidence: 99%

Kinetic theory of acoustic-like modes in nonextensive pair plasmas

Saberian

Esfandyari-Kalejahi

2013

Astrophys Space Sci

View full text Add to dashboard Cite

The low-frequency acoustic-like modes in a pair plasma (electron-positron or pairion) is studied by employing a kinetic theory model based on the Vlasov and Poisson's equation with emphasizing the Tsallis's nonextensive statistics. The possibility of the acoustic-like modes and their properties in both fully symmetric and temperatureasymmetric cases are examined by studying the dispersion relation, Landau damping and instability of modes. The resultant dispersion relation in this study is compatible with the acoustic branch of the experimental data [W. Oohara, D. Date, and R. Hatakeyama, Phys. Rev. Lett. 95, 175003 (2005)], in which the electrostatic waves have been examined in a pure pair-ion plasma. Particularly, our study reveals that the occurrence of growing or damped acoustic-like modes depends strongly on the nonextensivity of the system as a measure for describing the long-range Coulombic interactions and correlations in the plasma. The mechanism that leads to the unstable modes lies in the heart of the nonextensive formalism yet, the mechanism of damping is the same developed by Landau. Furthermore, the solutions of acoustic-like waves in an equilibrium Maxwellian pair plasma are recovered in the extensive limit (q → 1), where the acoustic modes have only the Landau damping and no growth.

show abstract

Section: Introductionmentioning

confidence: 99%

Kinetic theory of acoustic-like modes in nonextensive pair plasmas

Saberian

Esfandyari-Kalejahi

2013

Astrophys Space Sci

View full text Add to dashboard Cite

show abstract

“…1 While Penning traps are limited to the confinement of like-charged particles, a magnetic surface configuration such as that of a stellarator can confine plasmas of arbitrary neutrality. 2 This type of device is capable of exploring a wide range of new physical phenomena with relevance to basic plasma physics, particle physics, and fusion science. By introducing positrons into an electron plasma confined on magnetic surfaces, a plasma can be formed in which positrons are confined not only by the magnetic surfaces, but also by the potential well created by the electrons.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation of three-dimensional single-species plasma equilibria on magnetic surfaces

et al. 2005

Self Cite

View full text Add to dashboard Cite

Presented for the first time are numerical solutions to the three-dimensional nonlinear equilibrium equation for single-species plasmas confined on magnetic surfaces and surrounded by an equipotential boundary. The major-radial shift of such plasmas is found to be outward, qualitatively similar to the Shafranov shift of quasineutral plasmas confined on magnetic surfaces. However, this is the opposite of what occurs in the pure toroidal field equilibria of non-neutral plasmas (i.e., in the absence of magnetic surfaces). The effect of varying the number of Debye lengths in the plasma for the three-dimensional (3D) model is in agreement with previous 2D calculations: the potential varies significantly on magnetic surfaces for plasmas with few Debye lengths (a≲λd), and tends to be constant on surfaces when many Debye lengths are present (a≳10λd). For the case of a conducting boundary that does not conform to the outer magnetic surface, the plasma is shifted towards the conductor and the potential varies significantly on magnetic surfaces near the plasma edge. Debye shielding effects are clearly demonstrated when a nonuniform bias is applied to the boundary. Computed equilibrium profiles are presented for the Columbia Non-Neutral Torus [T. S. Pedersen, A. H. Boozer, J. P. Kermer, R. Lefrancois, F. Dahlgren, N. Pomphrey, W. Reiersen, and W. Dorland, Fusion Sci. Technol. 46, 200 (2004)], a stellarator designed to confine non-neutral plasmas.

show abstract

“…Pure toroidal traps [5,6] have been successfully used to confine nonneutral plasmas, and have also been used to study quasi-neutral plasmas [7], but have to date not yet confined and sustained partially neutralized plasmas. Stellarators, exhibiting closed particle orbits at any degree of neutralization, are predicted to be able to confine plasmas of arbitrary neutrality [8,9].…”

Section: Introductionmentioning

confidence: 99%

First experimental studies of the physics of plasmas of arbitrary degree of neutrality

Sarasola

Pedersen

2012

Plasma Phys. Control. Fusion

View full text Add to dashboard Cite

Abstract. The first detailed experimental characterization of the physics of plasmas of arbitrary neutrality is reported. It is shown that the degree of neutralization of the plasma in the Columbia Non-Neutral Torus stellarator can be varied continuously from quasi-neutral to pure electron plasma, and that the plasma can be sustained indefinitely at any degree of neutralization. The physical phenomena change significantly as the degree of neutralization is varied. Quasi-neutral plasmas exhibit a single mode low frequency flute instability. This mode aligns almost perfectly with the magnetic field lines, presenting a resonant m = 3 poloidal structure. For weakly magnetized ions, and moderate degrees of neutralization, multi-mode behaviour is observed, in some cases fully turbulent. At the other extreme of the neutralization scale, electron-rich plasmas with a small but non-negligible amount of ions exhibit single mode fluctuations. Essentially identical phenomena were previously reported by Marksteiner [Q. Marksteiner et al., 2008, Phys. Rev. Lett., 100, 065002]. In addition to the already known poloidal mode number m = 1 of these fluctuations, the toroidal mode number is now known: n = 0. This not only confirms the previous observations that the electron fluid force balance appears to be broken, but the frozen-in flux condition is also violated.

show abstract

Confinement of plasmas of arbitrary neutrality in a stellarator

Cited by 6 publications

References 18 publications

Kinetic theory of acoustic-like modes in nonextensive pair plasmas

Kinetic theory of acoustic-like modes in nonextensive pair plasmas

Numerical investigation of three-dimensional single-species plasma equilibria on magnetic surfaces

First experimental studies of the physics of plasmas of arbitrary degree of neutrality

Contact Info

Product

Resources

About