Quasi-linear relaxation of fast ions moving transverse to a magnetic field

Kulygin, V. M.; Mikhaǐlovskiǐ, A. B.; Tsapelkin, E. S.

doi:10.1088/0032-1028/13/12/003

Cited by 29 publications

(26 citation statements)

References 2 publications

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“…The electric field in the plume must then be calculated by balancing the pick-up current with field aligned currents carried by Alfven waves [Goertz, 1980], ) and form a ring distribution in velocity space which is unstable to electrostatic waves [Harris, 1959]. It is known that such a ring distribution will quasilinearly diffuse in velocity space with a rapid formation of a high energy tail [Kulygin et al, 1971], Table 2. Plasma density fluctuations during an FES release while the POP was on the Remote Manipulator System (see Fig.…”

Section: Discussionmentioning

confidence: 99%

Effects of chemical releases by the STS 3 Orbiter on the ionosphere

Pickett¹,

Murphy²,

Kurth³

et al. 1985

J. Geophys. Res.

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The Plasma Diagnostics Package, which was flown aboard STS-3 as part of the Office of Space Science first Shuttle payload (OSS-1), recorded the effects of various chemical releases from the Orbiter. Changes in the plasma environment were observed to occur during flash evaporator system releases, water dumps and maneuvering thruster operations. During flash evaporator operations, broadband Orbiter-generated electrostatic noise was enhanced and plasma density irregularities (AN/N) were observed to increase by 3 to 30 times with a spectrum which rose steeply and peaked below 6 Hz. Ions with energies up to several hundred eV were also observed during one flash evaporator operation. In the case of water dumps, background electrostatic noise was enhanced at frequencies below about 3 kHz and suppressed at frequencies above 3 kHz during the dump, and AN/N was also seen to increase by 5 to 6 times. Various changes in the plasma environment were effected by primary and vernier thruster operations, including increases in electron density by as much as 3 orders of magnitude, neutral pressure increases to as high as 10" 1 * torr from the nominal 10 torr, and perturbations in the spacecraft potential by several volts, particularly when measured relative to the plasma potential in the wake. Thruster activity also stimulated electrostatic noise with a spectrum which peaked at approximately 0.5 kHz. In addition, ions with energies up to 1 keV were seen during some thruster events.

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Section: Discussionmentioning

confidence: 99%

Effects of chemical releases by the STS 3 Orbiter on the ionosphere

Pickett¹,

Murphy²,

Kurth³

et al. 1985

J. Geophys. Res.

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“…11 " 13 The thermalization of these NBI ions by the lower hybrid mode 14 will afford a ready explanation for the presence of heavy ions in the warm particle halo as well as the broadband electrostatic noise referred to earlier.…”

Section: Institute Of Geophysics and Planetary Physics University Ofmentioning

confidence: 82%

Thermalization of Neutral-Beam-Injected Ions by Lower Hybrid Waves in Jupiter's Magnetosphere

Barbosa

1985

Phys. Rev. Lett.

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A theoretical analysis of lower hybrid wave generation by a ring distribution of superthermal ions is presented. A kinetic instability of waves traveling across the magnetic field occurs when fast neutrals escaping from the Io plasma torus are reionized and accelerated to corotation speed in Jupiter's magnetosphere, Instability is possible for modest threshold vaules of V/a 0 =3-7 where V is the pickup gyrospeed and a 0 is the background-ion thermal speed. Consequent effects include the relaxation of the pickup-ion distribution and the acceleration of superthermal electrons. PACS numbers: 52.40.Mj, 52.35.Qz, 52.50.Gj, 96.30.Kf The ionization of energetic neutral-atom beams in plasma is a practical means of auxiliary heating for fusion reactors under development. 1 The unencumbered simplicity of the scheme makes it likely that similar processes would be found in natural settings. 2 " 4 Indeed, the close parallelism of physical processes thought to occur in the Io plasma torus 5,6 with those in fusion plasmas is rather remarkable. In this paper we shall advance a common theoretical mechanism as an explanation for the presence of medium-energy particles and anomalous plasma-wave activity measured by the Voyager spacecraft at Jupiter.The problem concerns the observation of a type of broadband electrostatic noise in the outer parts of the Jovian magnetosphere with systematic morphological features. 7 The noise showed a propensity to be more intense in spatial regions where the plasma was cool ( -10 eV), thus exhibiting a sensitivity to ambient plasma temperature. 8 The plasma probe on the spacecraft 9 measured in situ a heterogeneous mixture of warm protons, sulfur, and oxygen ions (100 eV to 1 keV) composing a "halo" embedded in which was a stratum of cool, dense Iogenic heavy-ion plasma located at the centrifugal equator. Assessing all known plasma sources we concluded that the broadband noise, which included a prominent component near the lower hybrid (LH) frequency, was either a dissipation effect associated with radial transport outwards of the cool Iogenic plasma or a manifestation of energy exchange between superthermal ionospheric protons and Iogenic plasma. 8 A subsequent theoretical study uncovered another important mode of material transport that featured prominently in the mass and energy budget of the Jovian magnetosphere. It was found that charge exchange between corotating Io torus ions and the neutral-atom clouds that disperse off of Io produces an intense beam of fast neutral atoms that freely escape the magnetosphere in the form of an annular disc. 10 The reionization of these atoms forming this so-called magnetospheric neutral wind would recycle a fraction of Iogenic matter back into the magnetosphere. Con-sequentially, this would provide a significant heat source for the magnetosphere since the ionization "pickup" process at large radial distances extracts energy from the planetary rotation as the ions are swept up to corotation with comparable drift energy and gyroenergy.In this paper we analyz...

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“…(A3) is significantly smaller (for the parameters in Figure 8) than the fluctuation level obtained by assuming that the wave energy level (jE ES 2 j) is 10% of the free energy of the ring. 27 The hybrid simulations have also been used to infer an empirical scaling for the energy gained by the background ions, which equals the energy lost by the ring ions. This scaling also yields an expression for the percentage of energy lost by the ring ions, as a function of the ring velocity, density, and mass ratio.…”

Section: Results Showing Fluctuations Energy Loss By Ring Ion Heatingmentioning

confidence: 99%

Influence of plasma beta on the generation of lower hybrid and whistler waves by an ion velocity ring distribution

Winske

Daughton

2015

Physics of Plasmas

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We present results of three-dimensional electromagnetic particle-in-cell simulations of the lower hybrid ion ring instability, similar to our earlier results [D. Winske and W. Daughton, Phys. Plasma 19, 072109 (2012)], but at higher electron beta (b e ¼ ratio of electron thermal pressure to magnetic pressure ¼ 0.06, rather than at 0.006) with T i ¼ T e . At higher electron beta, the level of lower hybrid waves at saturation normalized to the ion thermal energy (b i ¼ 0.06 also) is only slightly smaller, but the corresponding magnetic fluctuations are about an order of magnitude larger, consistent with linear theory. After saturation, the waves evolve into whistler waves, through a number of possible mechanisms, with an average growth rate considerably smaller than the linear growth rate of the lower hybrid waves, to a peak fluctuation level that is about 20% above the lower hybrid wave saturation level. The ratio of the peak magnetic fluctuations associated with the whistler waves relative to those of the saturated lower hybrid waves, the ratio of the nonlinear growth rate of whistlers relative to the linear growth rate of lower hybrid waves, the amount of energy extracted from the ring, and the amount of heating of the background ions and electrons are comparable to those in the lower electron beta 3D simulation. This suggests that even at higher electron beta, the linear and nonlinear physics of the lower hybrid ion ring instability is dominated by electrostatic, wave-particle rather than wave-wave interactions.

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Quasi-linear relaxation of fast ions moving transverse to a magnetic field

Cited by 29 publications

References 2 publications

Effects of chemical releases by the STS 3 Orbiter on the ionosphere

Effects of chemical releases by the STS 3 Orbiter on the ionosphere

Thermalization of Neutral-Beam-Injected Ions by Lower Hybrid Waves in Jupiter's Magnetosphere

Influence of plasma beta on the generation of lower hybrid and whistler waves by an ion velocity ring distribution

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