Field-aligned plasma motion in the converging field line geometry of anisotropic plasma pressure

In our previous report (O. Saka, Adv. Polar Upper Atmos. Res., 19, 80, 2005), the steady-state flow characteristics in converging field line geometry has been examined by incorporating double adiabatic equations of state. In this report, we extend our previous analysis to examine how the penetration depth of plasma flow varies with a Mach number of the flow. The results obtained here suggest that the penetration depth became deeper than that of the mirror height of the single particle motion in all range of pressure anisotropy when a Mach number increased above 3.0. For a lower flow velocity, however, the flow could not penetrate below the mirror height of the single particle motion

Anti-diamagnetic (paramagnetic) properties of slow mode waves in anisotropic plasma pressures

In this report, we examined diamagnetic and anti-diamagnetic (paramagnetic) properties of magnetosonic modes in anisotropic fluid pressure condition by incorporating double adiabatic equations of state. In the context of liner perturbations, it is found that there appear two wave modes corresponding to a slow phase velocity and a fast phase velocity as is resembled to those in isotropic plasmas. For the fast phase velocity mode, pressure perturbations and field perturbations exhibited paramagnetic relations, similarly to isotropic plasmas. For the slow phase velocity mode, paramagnetic properties appear, unlike the isotropic case, at higher plasma beta part of lower pressure anisotropy (perpendicular/parallel) region

Plasma flow characteristics in converging field line geometry in anisotropic plasmas

Plasma flow characteristic in the anisotropic plasmas was examined in converging field lines by assuming the double adiabatic condition. When the pressure anisotropy disappears, the plasma flows behave as isotropic fluids; flows are decelerated/accelerated above/below the sound velocity. When the pressure anisotropy defined by P /Pz was below unity, the critical velocity that separates acceleration and decelerationincreasedabovethesoundvelocity. IntheoppositecasewhereP /Pz>1, the critical velocity decreased below the sound velocity. We suggest that a kinetic energy of the flow varies as the pressure anisotropy changes

Anti-diamagnetic (paramagnetic) properties of slow mode waves in anisotropic plasma pressures

Abstract: In this report, we examined diamagnetic and anti-diamagnetic (paramagnetic) properties of magnetosonic modes in anisotropic fluid pressure condition by incorporating double adiabatic equations of state. In the context of liner perturbations, it is found that there appear two wave modes corresponding to a slow phase velocity and a fast phase velocity as is resembled to those in isotropic plasmas. For the fast phase velocity mode, pressure perturbations and field perturbations exhibited paramagnetic relations, similarly to isotropic plasmas. For the slow phase velocity mode, paramagnetic properties appear, unlike the isotropic case, at higher plasma beta part of lower pressure anisotropy (perpendicular/parallel) region. key words: anisotropic plasmas, magnetosonic waves, diamagnetic and anti-diamagnetic propertie

The effect of magnetic mirror force on the field-aligned acceleration of plasmas

A magnetic mirror effect on the field-aligned acceleration of plasma flow is discussed for anisotropic plasma conditions by incorporating double adiabatic equations of state. In a non-uniform distribution of the field magnitude along the field lines, it is found that the field-aligned acceleration is toward higher field intensity region for the fluid of low thermal energy, while the acceleration is toward lower field intensity region for the fluid of high thermal energy. We infer that perpendicular pressure would cause such an energy-dependent behavior of the field-aligned acceleration through the magnetic mirror force

Simultaneous transients in the auroral zone and the equator as observed with SuperDARN and magnetometers: A correlation with equatorial counter electrojet (CEJ) event

An equatorial counter electrojet (CEJ) event characterized by a large amplitude (～150 nT) and a short duration (～15 min) magnetic disturbance occurred in the dayside region at 0053 UT, 23 October 1994. This event was detected by the ground magnetometers along the dayside dip-equator. The CEJ current, with local westward ionospheric currents, was located to the north of the normal eastward current (equatorial electrojet: EEJ) that existed prior to the CEJ event. Simultaneously with the occurrence of the CEJ event, an enhanced plasma convection with very high velocity (～2000 m/s) was observed by SuperDARN in the dusk sector of the auroral zone. These simultaneous occurrences in the auroral zone and at the equator may suggest that such an impulsive CEJ event could be inteipreted as a violation of the shielding of the high-latitude potential pattern