Effects of Ion Magnetization on the Farley–Buneman Instability in the Solar Chromosphere

Fletcher, Alex; Dimant, Y. S.; Oppenheim, M. M.; Fontenla, J. M.

doi:10.3847/1538-4357/aab71a

Cited by 7 publications

(4 citation statements)

References 30 publications

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“…Further improvement can be achieved by considering the same fundamental Equations but without assuming

δ n_{i} = δ n_{e}

and instead keeping perturbations for individual ion species separately, with

δ n = \sum_{j} δ n_{j} = δ n_{e}

. This approach has been previously implemented in studies of electrostatic instabilities in the solar chromosphere (Fletcher et al, 2018; Madsen et al, 2014; Oppenheim et al, 2020). Alternatively, both the momentum and energy equations can have modified collisional terms, for example, the momentum equation will become (e.g., Schunk & Nagy, 2000, their Equation 5.22b)

m_{α} \frac{D_{α}}{D t} {boldV}_{α} = q_{α} ((), boldE + {boldV}_{α} \times boldB) + \sum_{β} ν_{α β} m_{α} {normalΦ}_{α β} ((), {boldV}_{β} - {boldV}_{α}) - \frac{\nabla ((), n_{α} T_{α})}{n_{α}},

where the summation is over all ions and neutrals and Φ αβ is the correction factor describing a collision α − β that may depend on velocities and temperatures (Schunk & Nagy, 2000).…”

Section: Discussionmentioning

confidence: 99%

“…Further improvement can be achieved by considering the same fundamental Equations 1-3 but without assuming n i = n e and instead keeping perturbations for individual ion species separately, with n = ∑ n = n e . This approach has been previously implemented in studies of electrostatic instabilities in the solar chromosphere (Fletcher et al, 2018;Madsen et al, 2014;Oppenheim et al, 2020). Alternatively, both the momentum and energy equations can have modified collisional terms, for example, the momentum equation will become (e.g., Schunk & Nagy, 2000, their Equation 5.22b)…”

Section: Discussionmentioning

confidence: 99%

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Toward An Integrated View of Ionospheric Plasma Instabilities: 5. Ion‐Thermal Instability for Arbitrary Ion Magnetization, Density Gradient, and Wave Propagation

Makarevich

2020

JGR Space Physics

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A unified fluid theory of ionospheric electrostatic instabilities is presented that includes thermal effects due to nonisothermal processes for arbitrary ion magnetization, background density gradient, and wave propagation. The theory considers arbitrary altitude within the limits imposed by the fluid and collisional models and integrates the ion-thermal instability (ITI) with the Farley-Buneman and gradient-drift plasma instabilities (FBI and GDI). A general dispersion relation is obtained and solved numerically for the complex wave frequency by using either an iterative or a polynomial (quadric) form in. An analytic explicit expression for the instability growth rate is also derived under the local and slow growth approximations. The previously considered limiting cases of the FBI/ITI at long wavelengths and the FBI/GDI for isothermal plasma are successfully recovered. In the high-latitude E-region near 110 km in altitude, thermal effects are found to be destabilizing at long wavelengths near = 1,000 m and stabilizing at shorter wavelengths near 10 m. In the F-region, the effects are destabilizing at = 1,000 m but much weaker that those of GDI for moderate gradients. At shorter wavelengths, they become comparable so that a significant fraction of propagation directions at = 10 m have positive growth rates, in contrast with the isothermal FBI/GDI case, where stronger gradients are needed to destabilize the plasma at these short wavelengths. The overall conclusion is that the thermal effects modify the growth rate terms traditionally associated with FBI and GDI rather than being purely additive.

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“…Further improvement can be achieved by considering the same fundamental Equations but without assuming

δ n_{i} = δ n_{e}

and instead keeping perturbations for individual ion species separately, with

δ n = \sum_{j} δ n_{j} = δ n_{e}

m_{α} \frac{D_{α}}{D t} {boldV}_{α} = q_{α} ((), boldE + {boldV}_{α} \times boldB) + \sum_{β} ν_{α β} m_{α} {normalΦ}_{α β} ((), {boldV}_{β} - {boldV}_{α}) - \frac{\nabla ((), n_{α} T_{α})}{n_{α}},

where the summation is over all ions and neutrals and Φ αβ is the correction factor describing a collision α − β that may depend on velocities and temperatures (Schunk & Nagy, 2000).…”

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Toward An Integrated View of Ionospheric Plasma Instabilities: 5. Ion‐Thermal Instability for Arbitrary Ion Magnetization, Density Gradient, and Wave Propagation

Makarevich

2020

JGR Space Physics

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show abstract

“…The work by Fontenla (2005) and Fontenla et al (2008) treats the FB instability appropriately for the ionosphere, where it was originally discovered, but neglects crucial terms that become relevant in the chromosphere. Madsen et al (2014) include some such terms by treating the instability with a multifluid model yet neglects proton magnetization; Fletcher et al (2018) shows that ion magnetization effects reduce the prevalence of the instability in the chromosphere.…”

Section: Introductionmentioning

confidence: 99%

Multifluid Simulation of Solar Chromospheric Turbulence and Heating Due to Thermal Farley–Buneman Instability

Evans

Oppenheim

Martínez-Sykora

et al. 2023

ApJ

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Models fail to reproduce observations of the coldest parts of the Sun’s atmosphere, where interactions between multiple ionized and neutral species prevent an accurate MHD representation. This paper argues that a meter-scale electrostatic plasma instability develops in these regions and causes heating. We refer to this instability as the Thermal Farley–Buneman Instability (TFBI). Using parameters from a 2.5D radiative MHD Bifrost simulation, we show that the TFBI develops in many of the colder regions in the chromosphere. This paper also presents the first multifluid simulation of the TFBI and validates this new result by demonstrating close agreement with theory during the linear regime. The simulation eventually develops turbulence, and we characterize the resulting wave-driven heating, plasma transport, and turbulent motions. These results all contend that the effects of the TFBI contribute to the discrepancies between solar observations and radiative MHD models.

show abstract

“…The work by Fontenla (2005); Fontenla et al (2008) treats the FB instability appropriately for the ionosphere, where it was originally discovered, but neglects crucial terms that become relevant in the chromosphere. Madsen et al (2014) includes some such terms by treating the instability with a multi-fluid model, yet neglects proton magnetization; Fletcher et al (2018) shows that ion magnetization effects reduce the prevelance of the instability in the chromosphere.…”

Section: Introductionmentioning

confidence: 99%

Multi-fluid Simulation of Solar Chromospheric Turbulence and Heating Due to the Thermal Farley-Buneman Instability

Evans¹,

Oppenheim²,

Martínez-Sykora³

et al. 2022

Preprint

View full text Add to dashboard Cite

Models fail to reproduce observations of the coldest parts of the Sun's atmosphere, where interactions between multiple ionized and neutral species prevent an accurate MHD representation. This paper argues that a meter-scale electrostatic plasma instability develops in these regions and causes heating. We refer to this instability as the Thermal Farley-Buneman instability, or TFBI. Using parameters from a 2.5D radiative MHD Bifrost simulation, we show that the TFBI develops in many of the colder regions in the chromosphere. This paper also presents the first multi-fluid simulation of the TFBI and validates this new result by demonstrating close agreement with theory during the linear regime. The simulation eventually develops turbulence, and we characterize the resulting wave-driven heating, plasma transport, and random motions. These results all contend that effects of the TFBI contribute to the discrepancies between solar observations and radiative MHD models.

show abstract

Effects of Ion Magnetization on the Farley–Buneman Instability in the Solar Chromosphere

Cited by 7 publications

References 30 publications

Toward An Integrated View of Ionospheric Plasma Instabilities: 5. Ion‐Thermal Instability for Arbitrary Ion Magnetization, Density Gradient, and Wave Propagation

Toward An Integrated View of Ionospheric Plasma Instabilities: 5. Ion‐Thermal Instability for Arbitrary Ion Magnetization, Density Gradient, and Wave Propagation

Multifluid Simulation of Solar Chromospheric Turbulence and Heating Due to Thermal Farley–Buneman Instability

Multi-fluid Simulation of Solar Chromospheric Turbulence and Heating Due to the Thermal Farley-Buneman Instability

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