More Like this

1. Electrical conductivity of hot relativistic plasma in a strong magnetic field

   https://doi.org/10.1103/PhysRevD.110.096009  

   Ghosh, Ritesh; Shovkovy, Igor A (November 2024, Physical Review D)

   We employ first-principles quantum field theoretical methods to investigate the longitudinal and transverse electrical conductivities of a strongly magnetized hot quantum electrodynamics (QED) plasma at the leading order in coupling. The analysis employs the fermion damping rate in the Landau-level representation, calculated with full kinematics and exact amplitudes of one-to-two and two-to-one QED processes. In the relativistic regime, both conductivities exhibit an approximate scaling behavior described by ${\sigma }_{\parallel ,\perp }=T{\tilde{\sigma }}_{\parallel ,\perp }$, where ${\tilde{\sigma }}_{\parallel ,\perp }$are functions of the dimensionless ratio $\left|eB\right|/T^2$(with $T$denoting temperature and $B$magnetic field strength). We argue that the mechanisms for the transverse and longitudinal conductivities differ significantly, leading to a strong suppression of the former in comparison to the latter. Published by the American Physical Society2024 

   more » « less
2. Effects of Anisotropy on Strongly Magnetized Neutron and Strange Quark Stars in General Relativity

   https://doi.org/10.3847/1538-4357/ac222a  

   Deb, Debabrata; Mukhopadhyay, Banibrata; Weber, Fridolin (November 2021, The Astrophysical Journal)

   Abstract We investigate the properties of anisotropic, spherically symmetric compact stars, especially neutron stars (NSs) and strange quark stars (SQSs), made of strongly magnetized matter. The NSs are described by the SLy equation of state (EOS) and the SQSs by an EOS based on the MIT Bag model. The stellar models are based on an a priori assumed density dependence of the magnetic field and thus anisotropy. Our study shows that not only the presence of a strong magnetic field and anisotropy, but also the orientation of the magnetic field itself, have an important influence on the physical properties of stars. Two possible magnetic field orientations are considered: a radial orientation where the local magnetic fields point in the radial direction, and a transverse orientation, where the local magnetic fields are perpendicular to the radial direction. Interestingly, we find that for a transverse orientation of the magnetic field, the stars become more massive with increasing anisotropy and magnetic-field strength and increase in size since the repulsive, effective anisotropic force increases in this case. In the case of a radially oriented magnetic field, however, the masses and radii of the stars decrease with increasing magnetic-field strength because of the decreasing effective anisotropic force. Importantly, we also show that in order to achieve hydrostatic equilibrium configurations of magnetized matter, it is essential to account for both the local anisotropy effects as well as the anisotropy effects caused by a strong magnetic field. Otherwise, hydrostatic equilibrium is not achieved for magnetized stellar models. 

   more » « less
3. Generation of strong magnetic fields for magnetized plasma experiments at the 1-MA pulsed power machine

   https://doi.org/10.1063/5.0042863  

   Ivanov, V_V; Maximov, A_V; Betti, R.; Leal, L_S; Moody, J_D; Swanson, K_J; Huerta, N_A (May 2021, Matter and Radiation at Extremes)

   Pulsed power technology provides a platform for investigating plasmas in strong magnetic fields using a university-scale machine. Presented here are methods for generating and measuring the 1–4-MG magnetic fields developed for the 1-MA Zebra pulsed power generator at the University of Nevada, Reno. A laser coupled with the Zebra generator produces a magnetized plasma, and experiments investigate how a megagauss magnetic field affects the two-plasmon decay and the expansion of the laser-produced plasma in both transverse and longitudinal magnetic fields. 

   more » « less
4. Theory of the ion–electron temperature relaxation rate in strongly magnetized plasmas

   https://doi.org/10.1063/5.0146417  

   Jose, Louis; Baalrud, Scott D. (May 2023, Physics of Plasmas)

   Recent works have shown that strongly magnetized plasmas characterized by having a gyrofrequency greater than the plasma frequency exhibit novel transport properties. One example is that the friction force on a test charge shifts, obtaining components perpendicular to its velocity in addition to the typical stopping power component antiparallel to its velocity. Here, we apply a recent generalization of the Boltzmann equation for strongly magnetized plasmas to calculate the ion–electron temperature relaxation rate. Strong magnetization is generally found to increase the temperature relaxation rate perpendicular to the magnetic field and to cause the temperatures parallel and perpendicular to the magnetic field to not relax at equal rates. This, in turn, causes a temperature anisotropy to develop during the equilibration. Strong magnetization also breaks the symmetry of independence of the sign of the charges of the interacting particles on the collision rate, commonly known as the “Barkas effect.” It is found that the combination of oppositely charged interaction and strong magnetization causes the ion–electron parallel temperature relaxation rate to be significantly suppressed, scaling inversely proportional to the magnetic field strength. 

   more » « less
5. Preliminary study of plasma modes and electron-ion collisions in partially magnetized strongly coupled plasmas

   https://doi.org/10.1103/PhysRevE.109.015201  

   Pak, Chanhyun; Billings, Virginia; Schlitters, Matthew; Bergeson, Scott D; Murillo, Michael S (January 2024, Physical Review E)

   Magnetic fields influence ion transport in plasmas. Straightforward comparisons of experimental measurements with plasma theories are complicated when the plasma is inhomogeneous, far from equilibrium, or characterized by strong gradients. To better understand ion transport in a partially magnetized system, we study the hydrodynamic velocity and temperature evolution in an ultracold neutral plasma at intermediate values of the magnetic field. We observe a transverse, radial breathing mode that does not couple to the longitudinal velocity. The inhomogeneous density distribution gives rise to a shear velocity gradient that appears to be only weakly damped. This mode is excited by ion oscillations originating in the wings of the distribution where the plasma becomes non-neutral. The ion temperature shows evidence of an enhanced electron-ion collision rate in the presence of the magnetic field. Ultracold neutral plasmas provide a rich system for studying mode excitation and decay. 

   more » « less