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Al-Naseri, H. & Brodin, G. (2023). Applicability of the Klein-Gordon equation for pair production in vacuum and plasma. Physical review. E, 108(5), Article ID 055205.
Open this publication in new window or tab >>Applicability of the Klein-Gordon equation for pair production in vacuum and plasma
2023 (English)In: Physical review. E, ISSN 2470-0045, E-ISSN 2470-0053, Vol. 108, no 5, article id 055205Article in journal (Refereed) Published
Abstract [en]

In this paper, a phase-space description of electron-positron pair-creation will be applied, based on a Wigner transformation of the Klein-Gordon equation. The resulting theory is similar in many respects to the equations from the Dirac-Heisenberg-Wigner formalism. However, in the former case, all physics related to particle spin is neglected. In the present paper we compare the pair-production rate in vacuum and plasmas, with and without spin effects, in order to evaluate the accuracy and applicability of the spinless approximation. It is found that for modest frequencies of the electromagnetic field, the pair production rate of the Klein-Gordon theory is a good approximation to the Dirac theory, provided the matter density is small enough for Pauli blocking to be neglected, and a factor of two related to the difference in the vacuum energy density is compensated for.  

Place, publisher, year, edition, pages
American Physical Society, 2023
National Category
Fusion, Plasma and Space Physics
Research subject
Physics
Identifiers
urn:nbn:se:umu:diva-208015 (URN)10.1103/PhysRevE.108.055205 (DOI)2-s2.0-85177615325 (Scopus ID)
Funder
Knut and Alice Wallenberg Foundation
Note

Originally included in thesis in manuscript form. 

Available from: 2023-05-08 Created: 2023-05-08 Last updated: 2023-11-30Bibliographically approved
Brodin, G., Al-Naseri, H., Zamanian, J., Torgrimsson, G. & Eliasson, B. (2023). Plasma dynamics at the Schwinger limit and beyond. Physical review. E, 107(3), Article ID 035204.
Open this publication in new window or tab >>Plasma dynamics at the Schwinger limit and beyond
Show others...
2023 (English)In: Physical review. E, ISSN 2470-0045, E-ISSN 2470-0053, Vol. 107, no 3, article id 035204Article in journal (Refereed) Published
Abstract [en]

Strong field physics close to or above the Schwinger limit are typically studied with vacuum as initial condition or by considering test particle dynamics. However, with a plasma present initially, quantum relativistic mechanisms such as Schwinger pair creation are complemented by classical plasma nonlinearities. In this work we use the Dirac-Heisenberg-Wigner formalism to study the interplay between classical and quantum mechanical mechanisms in the regime of ultrastrong electric fields. In particular, the effects of initial density and temperature on the plasma oscillation dynamics are determined. Finally, comparisons with competing mechanisms such as radiation reaction and Breit-Wheeler pair production are made.

Place, publisher, year, edition, pages
American Physical Society, 2023
National Category
Fusion, Plasma and Space Physics
Research subject
Physics
Identifiers
urn:nbn:se:umu:diva-205903 (URN)10.1103/physreve.107.035204 (DOI)000957776100003 ()37073070 (PubMedID)2-s2.0-85151329265 (Scopus ID)
Funder
Swedish Research Council, 2020-04327
Available from: 2023-03-22 Created: 2023-03-22 Last updated: 2023-05-08Bibliographically approved
Al-Naseri, H. & Brodin, G. (2023). Ponderomotive force due to the intrinsic spin for electrostatic waves in a magnetized plasma. Physics of Plasmas, 30(6), Article ID 062109.
Open this publication in new window or tab >>Ponderomotive force due to the intrinsic spin for electrostatic waves in a magnetized plasma
2023 (English)In: Physics of Plasmas, ISSN 1070-664X, E-ISSN 1089-7674, Vol. 30, no 6, article id 062109Article in journal (Refereed) Published
Abstract [en]

We study the contribution from the electron spin to the ponderomotive force, using a quantum kinetic model, including the spin-orbit correction. Specifically, we derive an analytical expression for the ponderomotive force, applicable for electrostatic waves propagating parallel to an external magnetic field. To evaluate the expression, we focus on the case of Langmuir waves and on the case of the spin resonance wave mode, where the classical and spin contributions to the ponderomotive force are compared. Somewhat surprisingly, depending on the parameter regime, we find that the spin contribution to the ponderomotive force may dominate for the Langmuir wave, whereas the classical contribution can dominate for the spin resonance mode.

Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2023
National Category
Fusion, Plasma and Space Physics
Identifiers
urn:nbn:se:umu:diva-211798 (URN)10.1063/5.0147440 (DOI)001010958100001 ()2-s2.0-85162957066 (Scopus ID)
Available from: 2023-07-11 Created: 2023-07-11 Last updated: 2023-07-11Bibliographically approved
Al-Naseri, H. & Brodin, G. (2023). Radiation reaction effects in relativistic plasmas: the electrostatic limit. Physical review. E, 107(3), Article ID 035203.
Open this publication in new window or tab >>Radiation reaction effects in relativistic plasmas: the electrostatic limit
2023 (English)In: Physical review. E, ISSN 2470-0045, E-ISSN 2470-0053, Vol. 107, no 3, article id 035203Article in journal (Refereed) Published
Abstract [en]

We study the evolution of electrostatic plasma waves, using the relativistic Vlasov equation extended by the Landau-Lifshitz radiation reaction, accounting for the back-reaction due to the emission of single particle Larmor radiation. In particular, the Langmuir wave damping is calculated as a function of wave number, initial temperature, and initial electric field amplitude. Moreover, the background distribution function loses energy in the process, and we calculate the cooling rate as a function of initial temperature and initial wave amplitude. Finally, we investigate how the relative magnitude of wave damping and background cooling varies with the initial parameters. In particular, it is found that the relative contribution to the energy loss associated with background cooling decreases slowly with the initial wave amplitude.

Place, publisher, year, edition, pages
American Physical Society, 2023
National Category
Fusion, Plasma and Space Physics
Research subject
Physics
Identifiers
urn:nbn:se:umu:diva-205904 (URN)10.1103/physreve.107.035203 (DOI)000954805400003 ()37072971 (PubMedID)2-s2.0-85151338611 (Scopus ID)
Available from: 2023-03-22 Created: 2023-03-22 Last updated: 2023-05-08Bibliographically approved
Al-Naseri, H. & Brodin, G. (2022). Linear pair-creation damping of high-frequency plasma oscillation. Physics of Plasmas, 29(4), Article ID 042106.
Open this publication in new window or tab >>Linear pair-creation damping of high-frequency plasma oscillation
2022 (English)In: Physics of Plasmas, ISSN 1070-664X, E-ISSN 1089-7674, Vol. 29, no 4, article id 042106Article in journal (Refereed) Published
Abstract [en]

We have studied the linear dispersion relation for Langmuir waves in plasmas of very high density, based on the Dirac-Heisenberg-Wigner formalism. The vacuum contribution to the physical observables leads to ultraviolet divergences, which are removed by a charge renormalization. The remaining vacuum contribution is small and is in agreement with previously derived expressions for the time-dependent vacuum polarization. The main new feature of the theory is a damping mechanism similar to Landau damping, but where the plasmon energy gives rise to creation of electron-positron pairs. The dependence of the damping rate (pair-creation rate) on the wavenumber, temperature, and density is analyzed. Finally, the analytical results of linearized theory are compared with numerical solutions.

Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2022
National Category
Fusion, Plasma and Space Physics Condensed Matter Physics
Identifiers
urn:nbn:se:umu:diva-194333 (URN)10.1063/5.0087085 (DOI)000788793900002 ()2-s2.0-85128402117 (Scopus ID)
Available from: 2022-05-04 Created: 2022-05-04 Last updated: 2023-05-08Bibliographically approved
Brodin, G. & Zamanian, J. (2022). Quantum kinetic theory of plasmas. Reviews of Modern Plasma Physics, 6(1), Article ID 4.
Open this publication in new window or tab >>Quantum kinetic theory of plasmas
2022 (English)In: Reviews of Modern Plasma Physics, E-ISSN 2367-3192, Vol. 6, no 1, article id 4Article, review/survey (Refereed) Published
Abstract [en]

As is well known, for plasmas of high density and modest temperature, the classical kinetic theory needs to be extended. Such extensions can be based on the Schrödinger Hamiltonian, applying a Wigner transform of the density matrix, in which case the Vlasov equation is replaced by the celebrated Wigner–Moyal equation. Extending the treatment to more complicated models, we investigate aspects such as spin dynamics (based on the Pauli Hamiltonian), exchange effects (using the Hartree–Fock approximation), Landau quantization, and quantum relativistic theory. In the relativistic theory, we first study cases where the field strength is well-beyond Schwinger critical field. Both weakly relativistic theory (gamma factors close to unity) and strongly relativistic theory are investigated, using assumptions that allow for a separation of electron and positron states. Finally, we study the so-called Dirac–Heisenberg–Wigner (DHW) formalism, which is a fully quantum relativistic theory, allowing for field strengths of the order of the Schwinger critical field or even larger. As a result, the quantum kinetic theory is extended to cover phenomena such as Zitterbewegung and electron–positron pair creation. While the focus of this review is on the quantum kinetic models, we illustrate the theories with various applications throughout the manuscript.

Place, publisher, year, edition, pages
Springer, 2022
Keywords
Density matrix, Dirac–Heisenberg–Wigner formalism, Exchange effects, Landau quantization, Quantum kinetic theory, Wigner transform
National Category
Fusion, Plasma and Space Physics Theoretical Chemistry
Identifiers
urn:nbn:se:umu:diva-212624 (URN)10.1007/s41614-022-00065-5 (DOI)2-s2.0-85128403603 (Scopus ID)
Available from: 2023-08-21 Created: 2023-08-21 Last updated: 2023-08-21Bibliographically approved
Misra, A. P. & Brodin, G. (2022). Wave-particle interactions in quantum plasmas. Reviews of Modern Plasma Physics, 6(1), Article ID 5.
Open this publication in new window or tab >>Wave-particle interactions in quantum plasmas
2022 (English)In: Reviews of Modern Plasma Physics, E-ISSN 2367-3192, Vol. 6, no 1, article id 5Article, review/survey (Refereed) Published
Abstract [en]

Wave-particle interaction (WPI) is one of the most fundamental processes in plasma physics in which one most prominent example is the Landau damping. Owing to its excellent energy-exchange mechanism, the WPI has gained increasing interest not only from theoretical points of view, but also its many important applications including plasma heating and plasma acceleration. In this review work, we present theoretical backgrounds of linear and nonlinear wave-particle interactions in quantum plasmas. Specifically, we focus on the wave-particle interactions for homogeneous plasma waves (i.e., waves with infinite extent rather than a localized pulse) as well as for propagating electrostatic waves in the weak and strong quantum regimes to demonstrate the modifications of several classical features including those associated with resonant and trapped particles. Finally, the future perspectives of WPI in quantum plasmas are presented.

Place, publisher, year, edition, pages
Springer, 2022
Keywords
Landau damping, Multi-plasmon resonance, Quantum plasma, Spin induced resonance, Wave-particle interaction
National Category
Fusion, Plasma and Space Physics
Identifiers
urn:nbn:se:umu:diva-212553 (URN)10.1007/s41614-022-00063-7 (DOI)2-s2.0-85128359582 (Scopus ID)
Available from: 2023-08-07 Created: 2023-08-07 Last updated: 2023-08-07Bibliographically approved
Misra, A. P., Chatterjee, D. & Brodin, G. (2021). Landau damping of electron-acoustic waves due to multi-plasmon resonances. Physics of Plasmas, 28(11), Article ID 0061716.
Open this publication in new window or tab >>Landau damping of electron-acoustic waves due to multi-plasmon resonances
2021 (English)In: Physics of Plasmas, ISSN 1070-664X, E-ISSN 1089-7674, Vol. 28, no 11, article id 0061716Article in journal (Refereed) Published
Abstract [en]

The linear and nonlinear theories of electron-acoustic waves (EAWs) are studied in a partially degenerate quantum plasma with two-temperature electrons and stationary ions. The initial equilibrium of electrons is assumed to be given by the Fermi-Dirac distribution at finite temperature. By employing the multi-scale asymptotic expansion technique to the one-dimensional Wigner-Moyal and Poisson equations, it is shown that the effects of multi-plasmon resonances lead to a modified complex Korteweg-de Vries (KdV) equation with a new nonlocal nonlinearity. In addition to giving rise to a nonlocal nonlinear term, the wave-particle resonance also modifies the local nonlinear coupling coefficient of the KdV equation. The latter is shown to conserve the number of particles; however, the wave energy decays with time. A careful analysis shows that the two-plasmon resonance is the dominant mechanism for nonlinear Landau damping of EAWs. An approximate soliton solution of the KdV equation is also obtained, and it is shown that the nonlinear Landau damping causes the wave amplitude to decay slowly with time compared to the classical theory.

Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2021
National Category
Fusion, Plasma and Space Physics
Identifiers
urn:nbn:se:umu:diva-189885 (URN)10.1063/5.0061716 (DOI)000715858600006 ()2-s2.0-85119187668 (Scopus ID)
Note

Erratum: Amar P. Misra, Debjani Chatterjee, and Gert Brodin , "Erratum: “Landau damping of electron-acoustic waves due to multi-plasmon resonances” [Phys. Plasmas 28, 112102 (2021)]", Physics of Plasmas 29, 029901 (2022) DOI: 10.1063/5.0084608

Available from: 2021-11-25 Created: 2021-11-25 Last updated: 2022-02-22Bibliographically approved
Al-Naseri, H., Zamanian, J. & Brodin, G. (2021). Plasma dynamics and vacuum pair creation using the Dirac-Heisenberg-Wigner formalism. Physical review. E, 104(1), Article ID 015207.
Open this publication in new window or tab >>Plasma dynamics and vacuum pair creation using the Dirac-Heisenberg-Wigner formalism
2021 (English)In: Physical review. E, ISSN 2470-0045, E-ISSN 2470-0053, Vol. 104, no 1, article id 015207Article in journal (Refereed) Published
Abstract [en]

We derive a system of coupled partial differential equations for the equal-time Wigner function in an arbitrary strong electromagnetic field using the Dirac-Heisenberg-Wigner formalism. In the electrostatic limit, we present a system of four coupled partial differential equations, which are completed by Ampères law. This electrostatic system is further studied for two different cases. In the first case, we consider linearized wave propagation in a plasma accounting for the nonzero vacuum expectation values. We then derive the dispersion relation and compare it with well-known limiting cases. In the second case, we consider Schwinger pair production using the local density approximation to allow for analytical treatment. The dependence of the pair production rate on the perpendicular momentum is investigated and it turns out that the spread of the produced pairs along with perpendicular momentum depends on the strength of the applied electric field.

Place, publisher, year, edition, pages
American Physical Society, 2021
National Category
Fusion, Plasma and Space Physics
Identifiers
urn:nbn:se:umu:diva-186411 (URN)10.1103/PhysRevE.104.015207 (DOI)000674387800007 ()2-s2.0-85110430469 (Scopus ID)
Available from: 2021-07-29 Created: 2021-07-29 Last updated: 2023-05-08Bibliographically approved
Ekman, R., Al-Naseri, H., Zamanian, J. & Brodin, G. (2021). Short-scale quantum kinetic theory including spin-orbit interactions. European Physical Journal D: Atomic, Molecular and Optical Physics, 75(1), Article ID 29.
Open this publication in new window or tab >>Short-scale quantum kinetic theory including spin-orbit interactions
2021 (English)In: European Physical Journal D: Atomic, Molecular and Optical Physics, ISSN 1434-6060, E-ISSN 1434-6079, Vol. 75, no 1, article id 29Article in journal (Refereed) Published
Abstract [en]

We present a quantum kinetic theory for spin-1/2 particles, including the spin-orbit interaction, retaining particle dispersive effects to all orders in ℏ, based on a gauge-invariant Wigner transformation. Compared to previous works, the spin-orbit interaction leads to a new term in the kinetic equation, containing both the electric and magnetic fields. Like other models with spin-orbit interactions, our model features "hidden momentum". As an example application, we calculate the dispersion relation for linear electrostatic waves in a magnetized plasma, and electromagnetic waves in a unmagnetized plasma. In the former case, we compare the Landau damping due to spin-orbit interactions to that due to the free current. We also discuss our model in relation to previously published works. 

Place, publisher, year, edition, pages
Springer, 2021
National Category
Fusion, Plasma and Space Physics
Research subject
Theoretical Physics
Identifiers
urn:nbn:se:umu:diva-162462 (URN)10.1140/epjd/s10053-020-00021-3 (DOI)000612852200013 ()2-s2.0-85099929253 (Scopus ID)
Funder
Swedish Research Council, 2016-03806Knut and Alice Wallenberg Foundation
Note

Previously included in thesis in manuscript form. 

Manuscript available at https://arxiv.org/abs/1908.05131

Available from: 2019-08-20 Created: 2019-08-20 Last updated: 2023-03-22Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0003-2716-098x

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