Solar Energetic Ions Created in a Reconnection Layer by Alfvén Wave Pickup

Wu, C. S.; Li, Y.; Chao, J. K.; Yoon, Peter H.; Lee, L. C.

doi:10.1086/305314

Cited by 17 publications

(15 citation statements)

References 13 publications

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“…An important point is that the maximum energy attainable by the newborn protons obtained in the simulations is consistent to that estimated in Wu (1996). Moreover, we conclude that the present two-dimensional result supports the intuitive estimate as well as the earlier one-dimensional result discussed in Wu et al (1998).…”

Section: Fig 4èsame Format As Insupporting

confidence: 90%

“…In an attempt to demonstrate the hypothesis put forth by Wu (1996), Wu et al (1998) have carried out numerical simulations based on a one-dimensional hybrid code under the postulate that the acceleration process can be accomplished very quickly, making the one-dimensional approximation justiÐable. Indeed, one-dimensional simulations have been very successful in the study of cometary newborn ions.…”

Section: Two-dimensional Simulationsmentioning

confidence: 99%

“…First, it is not the purpose of the present paper to discuss the general physics of solar Ñares, although our discussion adopts the idea that magnetic Ðeld reconnection plays a key role in solar Ñares (e.g., Sturrock 1966Sturrock , 1980Heyvaerts, Priest, & Rust 1977). Second, the present discussion is a continuation and elaboration of the study initiated by Wu (1996) and Wu et al (1998). The preceding papers placed emphasis on the physical concept, whereas the objective of the present discussion is to demonstrate by numerical simulation that the conjectured process is viable.…”

Section: Introductionmentioning

confidence: 95%

“…The preceding papers placed emphasis on the physical concept, whereas the objective of the present discussion is to demonstrate by numerical simulation that the conjectured process is viable. Although in Wu et al (1998) one-dimensional hybrid simulation has already been used to provide a qualitative and approximate discussion, it is desirable to study the problem with a simulation code that can describe a more realistic situation.…”

Section: Introductionmentioning

confidence: 99%

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A Source of Energetic Particles Associated with Solar Flares

Wang

et al. 2001

ApJ

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Energetic particles produced at a solar Ñare event are an issue of great theoretical interest. A scenario involving magnetic Ðeld reconnection and newborn ions produced by ionization of neutral atoms in the lower corona is proposed by Wu. A series of two-dimensional hybrid simulations has been carried out to investigate this scenario further, and the results are presented in this paper. It is shown that under certain conditions the proposed process can produce protons with energies in the range of 10È100 MeV with a timescale of 10~4 to 10~3 s in a reconnection layer via the so-called ion pickup process. The acceleration process is sensitive to the ambient magnetic Ðeld. The maximum energy attainable is also discussed in terms of altitudes above the photosphere on the basis of a certain magnetic Ðeld model.

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Section: Fig 4èsame Format As Insupporting

confidence: 90%

Section: Two-dimensional Simulationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

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A Source of Energetic Particles Associated with Solar Flares

Wang

et al. 2001

ApJ

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“…Recently, however, Wu (1996), Wu et al (1998), and Wang et al (2001) considered collisional charge-exchange of neutral hydrogen with protons in the outflow regions of solar magnetic reconnection sites. They showed that this 'pickup' process naturally forms ion ring distributions, as described in the next section.…”

Section: Introductionmentioning

confidence: 99%

Lower Hybrid Drive in Solar Magnetic Reconnection Regions: Implications for Electron Acceleration and Solar Heating

Cairns

2001

Publ. – Astron. Soc. Aust

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Lower hybrid (LH) drive involves the resonant acceleration of electrons parallel to the magnetic field by lower hybrid waves, often driven by ions with ring or ring-beam distributions. Charge-exchange between hydrogen atoms and protons with relative motions perpendicular to the magnetic field leads to ring distributions of pickup ions, with concomitant perpedicular ion ‘heating’. This paper considers the combination of LH drive and charge-exchange in the outflow regions of magnetic reconnection sites in the solar chromosphere and lower corona, showing that the combined mechanism naturally predicts major perpendicular ion heating and parallel electron acceleration, and exploring the mechanism’s relevance to specific solar reconnection phenomena, heating of the solar atmosphere, and production of energetic electrons that generate solar radio emission. Although primarily qualitative, analysis shows that the mechanism has numerous attractive aspects, including perpendicular ion heating that increases linearly with ion mass, parallel electron acceleration, predicted ion and electron temperatures that span those of the chromosphere and lower corona, and parallel electron speeds spanning those for type III bursts. Applications to chromospheric explosive events and low-lying active regions, and to heating the chromosphere, appear particularly suitable. Sweeping of plasma frozen-in to chromospheric and coronal magnetic field lines across the neutral atmosphere due to motions of sub-photospheric fields represents an obvious and important generalisation of the mechanism away from reconnection sites. The requirements that the neutrals not be strongly collisionally coupled to the plasma and that sufficient neutrals are available for charge-exchange restricts the LH drive mechanism to above the photosphere but below where the corona is essentially fully ionised. LH drive may thus be important in heating the chromosphere and low corona while other heating mechanisms dominate at higher altitudes. Although attractive thus far, quantitative analyses of LH drive in these contexts are necessary before definitive conclusions are reached.

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Energy budget and mechanisms of cold ion heating in asymmetric magnetic reconnection

et al. 2017

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Cold ions (few tens of eV) of ionospheric origin are commonly observed on the magnetospheric side of the Earth's dayside magnetopause. As a result, they can participate in magnetic reconnection, changing locally the reconnection rate and being accelerated and heated. We present four events where cold ion heating was observed by the Magnetospheric Multiscale mission, associated with the magnetospheric Hall E field region of magnetic reconnection. For two of the events the cold ion density was small compared to the magnetosheath density, and the cold ions were heated roughly to the same temperature as magnetosheath ions inside the exhaust. On the other hand, for the other two events the cold ion density was comparable to the magnetosheath density and the cold ion heating observed was significantly smaller. Magnetic reconnection converts magnetic energy into particle energy, and ion heating is known to dominate the energy partition. We find that at least 10–25% of the energy spent by reconnection into ion heating went into magnetospheric cold ion heating. The total energy budget for cold ions may be even higher when properly accounting for the heavier species, namely helium and oxygen. Large E field fluctuations are observed in this cold ion heating region, i.e., gradients and waves, that are likely the source of particle energization.

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Solar Energetic Ions Created in a Reconnection Layer by Alfvén Wave Pickup

Cited by 17 publications

References 13 publications

A Source of Energetic Particles Associated with Solar Flares

A Source of Energetic Particles Associated with Solar Flares

Lower Hybrid Drive in Solar Magnetic Reconnection Regions: Implications for Electron Acceleration and Solar Heating

Energy budget and mechanisms of cold ion heating in asymmetric magnetic reconnection

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