Diamagnetic current does not produce an instability in the solar corona

Vranjes, Jovo; Poedts, Stefaan

doi:10.1051/0004-6361/200811356

Cited by 5 publications

(4 citation statements)

References 9 publications

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“…In collisional plasma, such as in this experiment or within the solar photosphere and chromosphere, the growth of diamagnetic currents and their associated drift modes can be attributed to electron collisions. This growth is particularly prominent when there are transverse thermal pressure gradients coupled with plasma flows and electrical currents aligned with the magnetic field lines (Saleem et al 2007;Vranjes & Poedts 2009).…”

Section: Resultsmentioning

confidence: 99%

Dynamic Formation of a Transient Jet from Arched Magnetized Laboratory Plasma

Sklodowski

Tripathi

Carter

2023

ApJ

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A laboratory plasma experiment was built to explore the eruptive behavior of arched magnetized plasmas with dimensionless parameters relevant to the Sun’s photosphere (β ≈ 10−3, Lundquist number ≈104, plasma radius/ion gyroradius ≈20, ion–neutral collision frequency ≫ion cyclotron frequency). Dynamic formation of a transient plasma jet was observed in the presence of the strapping magnetic field. The eruption leading to the jet is unintuitive because the arched plasma is both kink- and torus-stable. The jet structure erupts within a few Alfvén transit times from the formation of the arched plasma. Extensive measurements of plasma temperature, density, magnetic field, and flows are presented. In its early stages, the jet plasma flows away from the arch with supersonic speeds (Mach 1.5). This high-speed flow persists up to the resistive diffusion time in the arched plasma and is driven by large gradients in the magnetic and thermal pressures near the birthplace of jets. There are two distinct electric current channels within the jet, one consisting of outgoing electrons and another composed of electrons returning to the anode footpoint. Significant current density around the jet is a consequence of the diamagnetic current produced by a large thermal pressure gradient in the jet. Ion–neutral charge-exchange collisions provide an efficient mechanism to produce the cross-field current and control the dynamics of the complex current channels of the jet.

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Section: Resultsmentioning

confidence: 99%

Dynamic Formation of a Transient Jet from Arched Magnetized Laboratory Plasma

Sklodowski

Tripathi

Carter

2023

ApJ

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“…In Eq. ( 4) the equilibrium diamagnetic drift contribution is exactly zero as long as the magnetic field is constant (Weiland [35], Vranjes and Poedts [27]). Hence, for perturbations of the shape f (x) exp(−iωt + ikz), from Eqs.…”

Section: Derivation Of Wave Equationmentioning

confidence: 99%

New features of ion acoustic waves in inhomogeneous and permeating plasmas

Vranjes

2013

A&A

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Context. It is generally accepted that the ion acoustic (IA) wave in plasmas containing ions and electrons with the same temperature is of minor importance due to strong damping of the wave by hot resonant ions. Aims. In this work it will be shown that the IA wave is susceptible to excitation even in hot-ion plasmas when both an electromagnetic transverse wave and a background density gradient are present in the plasma and, in addition, the wave is unstable (i.e., growing) in the case of permeating homogeneous plasmas. Methods. The multi-component fluid theory is used to describe the IA wave susceptibility for excitation in inhomogeneous plasmas and its coupling with electromagnetic waves. The growing IA wave in permeating homogeneous plasmas is described by the kinetic theory.Results. In plasmas with density and temperature gradients, the IA wave is effectively coupled with the electromagnetic waves. In comparison to the ordinary IA wave in homogeneous plasma, the Landau damping of the present wave is much smaller; to demonstrate this effect, a simple but accurate fluid model is presented for the Landau damping. In the case of permeating plasmas, a kinetic mechanism for the currentless IA wave instability is presented; it has a very low threshold for excitation compared with ordinary electron-current-driven kinetic instability. Such growing IA waves can effectively heat plasma in the upper solar atmosphere by a stochastic heating mechanism presented in the work. Conclusions. The results presented in the work suggest that the role of the IA wave in the heating of the solar atmosphere (chromosphere and corona) should be reexamined.

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“…In some situations, in plasmas with relatively cold ions, as a first approximation one may assume the E × B drift as the leading order one, and set it into the velocity v i⊥ in the polarization drift. The diamagnetic drift does not contribute to the ion flux ∇· ( n v *i ) ≡ 0, and also its contribution to the convective derivative of the polarization drift is cancelled by the part of the stress tensor flux n v π i (Vranjes & Poedts 2009e). Therefore, we shall focus now on the E × B drift, and the polarization drift v pi = (d E ⊥ /d t )/( B 0 Ω i ), where E ⊥ ≡− e y k y φ 1 .…”

Section: Physical Mechanism Of Heating By the Drift Wavementioning

confidence: 99%

Drift waves in the corona: heating and acceleration of ions at frequencies far below the gyrofrequency

Vranjes¹,

Poedts²

2010

Monthly Notices of the Royal Astronomical Society

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In the solar corona, several mechanisms of the drift wave instability can make the mode grow to amplitudes at which particle acceleration and stochastic heating by the drift wave take place. The stochastic heating, well known from laboratory plasma physics where it has been confirmed in numerous experiments, has been completely ignored in past studies of coronal heating. However, in the present study and in our very recent works it has been shown that the inhomogeneous coronal plasma is, in fact, a perfect environment for fast growing drift waves. As a matter of fact, the large growth rates are typically of the same order as the wave frequency. The consequent heating rates may exceed the required values for sustained coronal heating by several orders of magnitude. Some aspects of these phenomena are investigated here. In particular, the analysis of the particle dynamics within the growing wave is compared with the corresponding fluid analysis. While both of them predict the stochastic heating, the threshold for the heating obtained from the single particle analysis is higher. The explanation for this effect is given.

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Diamagnetic current does not produce an instability in the solar corona

Cited by 5 publications

References 9 publications

Dynamic Formation of a Transient Jet from Arched Magnetized Laboratory Plasma

Dynamic Formation of a Transient Jet from Arched Magnetized Laboratory Plasma

New features of ion acoustic waves in inhomogeneous and permeating plasmas

Drift waves in the corona: heating and acceleration of ions at frequencies far below the gyrofrequency

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