The Connection of Type Ii Spicules to the Corona

Judge, P. G.; Pontieu, Bart De; McIntosh, Scott W.; Olluri, Kosovare

doi:10.1088/0004-637x/746/2/158

Cited by 28 publications

(28 citation statements)

References 42 publications

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“…However, the pressure driven jets (e.g. Martínez-Sykora, Hansteen, and Moreno-Insertis (2011); Judge et al (2012)) are reported to gain speeds ∼ 60 km s −1 only. Thus, based on the above mentioned numerical simulation results along with our observations, it can be concluded that the evolution of magnetic field at small scales has a key role in the generation and acceleration of high-speed jets in the chromosphere and TR.…”

Section: Resultsmentioning

confidence: 99%

Statistical Study of Network Jets Observed in the Solar Transition Region: a Comparison Between Coronal Holes and Quiet-Sun Regions

et al. 2016

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Recent IRIS observations have revealed a prevalence of intermittent small-scale jets with apparent speeds of 80 -250 km s −1 , emanating from smallscale bright regions inside network boundaries of coronal holes. We find that these network jets appear not only in coronal holes but also in quiet-sun regions. Using IRIS 1330Å (C II) slit-jaw images, we extract several parameters of these network jets, e.g. apparent speed, length, lifetime and increase in foot-point brightness. Using several observations, we find that some properties of the jets are very similar but others are obviously different between the quiet sun and coronal holes. For example, our study shows that the coronal-hole jets appear to be faster and longer than those in the quiet sun. This can be directly attributed to a difference in the magnetic configuration of the two regions with open magnetic field lines rooted in coronal holes and magnetic loops often present in quiet sun. We have also detected compact bright loops, likely transition region loops, mostly in quiet sun. These small loop-like regions are generally devoid of network jets. In spite of different magnetic structures in the coronal hole and quiet sun in the transition region, there appears to be no substantial difference for the increase in foot-point brightness of the jets, which suggests that the generation mechanism of these network jets is likely the same in both regions.

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Section: Resultsmentioning

confidence: 99%

Statistical Study of Network Jets Observed in the Solar Transition Region: a Comparison Between Coronal Holes and Quiet-Sun Regions

et al. 2016

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“…The authors concluded that a rapid increase of Si iv over O iv is a signature of non-equilibrium ionization. Judge et al (2012) studied the non-equilibrium ionization effects in H, He, C, N, O, and Si during and after the heating of chromospheric plasma described by 1-D hydrodynamic equations. In their model, the chromospheric plasma at heights of about 2 Mm was first heated and accelerated upward for about 30 s (model A therein), and then heated for another 30 s, until coronal temperatures of about 1 MK were reached.…”

Section: -D Hydrodynamic Modellingmentioning

confidence: 99%

Nonequilibrium Processes in the Solar Corona, Transition Region, Flares, and Solar Wind (Invited Review)

et al. 2017

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We review the presence and signatures of the non-equilibrium processes, both non-Maxwellian distributions and non-equilibrium ionization, in the solar transition region, corona, solar wind, and flares. Basic properties of the non-Maxwellian distributions are described together with their influence on the heat flux as well as on the rates of individual collisional processes and the resulting optically thin synthetic spectra. Constraints on the presence of highenergy electrons from observations are reviewed, including positive detection of non-Maxwellian distributions in the solar corona, transition region, flares, and wind. Occurrence of non-equilibrium ionization is reviewed as well, especially in connection to hydrodynamic and generalized collisional-radiative modelling. Predicted spectroscopic signatures of non-equilibrium ionization depending on the assumed plasma conditions are summarized. Finally, we discuss the future remote-sensing instrumentation that can be used for detection of these non-equilibrium phenomena in various spectral ranges.

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“…Recently, Martiunez-Sykora et al (2017a) used the same model as the current paper to propose a new spicule formation mechanism that can reproduce the observed properties of spicules. This model has the potential to resolve some of the remaining unresolved issues with respect to the impact of spicules on the TR and corona Madjarska et al 2011;Judge et al 2012). Other phenomena are better understood, but current models cannot fully capture some of their properties, e.g., the length and lifetime of dynamic fibrils (Suematsu et al 1995;Hansteen et al 2006;Heggland et al 2007;Martínez-Sykora et al 2009b;Iijima & Yokoyama 2015).…”

Section: Introductionmentioning

confidence: 99%

Two-dimensional Radiative Magnetohydrodynamic Simulations of Partial Ionization in the Chromosphere. II. Dynamics and Energetics of the Low Solar Atmosphere

Martínez-Sykora

Pontieu

Carlsson

et al. 2017

ApJ

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We investigate the effects of interactions between ions and neutrals on the chromosphere and overlying corona using 2.5D radiative MHD simulations with the Bifrost code. We have extended the code capabilities implementing ion-neutral interaction effects using the generalized Ohm's law, i.e., we include the Hall term and the ambipolar diffusion (Pedersen dissipation) in the induction equation. Our models span from the upper convection zone to the corona, with the photosphere, chromosphere, and transition region partially ionized. Our simulations reveal that the interactions between ionized particles and neutral particles have important consequences for the magnetothermodynamics of these modeled layers: (1) ambipolar diffusion increases the temperature in the chromosphere; (2) sporadically the horizontal magnetic field in the photosphere is diffused into the chromosphere, due to the large ambipolar diffusion; (3) ambipolar diffusion concentrates electrical currents, leading to more violent jets and reconnection processes, resulting in (3a) the formation of longer and faster spicules, (3b) heating of plasma during the spicule evolution, and (3c) decoupling of the plasma and magnetic field in spicules. Our results indicate that ambipolar diffusion is a critical ingredient for understanding the magnetothermodynamic properties in the chromosphere and transition region. The numerical simulations have been made publicly available, similar to previous Bifrost simulations. This will allow the community to study realistic numerical simulations with a wider range of magnetic field configurations and physics modules than previously possible.

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The Connection of Type Ii Spicules to the Corona

Cited by 28 publications

References 42 publications

Statistical Study of Network Jets Observed in the Solar Transition Region: a Comparison Between Coronal Holes and Quiet-Sun Regions

Statistical Study of Network Jets Observed in the Solar Transition Region: a Comparison Between Coronal Holes and Quiet-Sun Regions

Nonequilibrium Processes in the Solar Corona, Transition Region, Flares, and Solar Wind (Invited Review)

Two-dimensional Radiative Magnetohydrodynamic Simulations of Partial Ionization in the Chromosphere. II. Dynamics and Energetics of the Low Solar Atmosphere

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