Laboratory simulations of solar prominence eruptions

Bellan, Paul M.; Hansen, J. F.

doi:10.1063/1.872870

Cited by 42 publications

(44 citation statements)

References 24 publications

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“…Our modeling of the driving mechanism of the system was inspired by laboratory simulations of prominence eruptions (Bellan & Hansen 1998 ;Hansen & Bellan 2001) and is qualitatively similar to recent observations of rotating photospheric Ñows (Nightingale et al 2000). By assuming that (1) the base plane dynamics is determined by the tangential electric Ðeld and (2) the electric current J at E t this plane has no tangential component, we calculate the base plane tangential velocity Ðeld from the ¿ t \ (v x , v y ) MHD OhmÏs law as follows :…”

Section: Model Descriptionmentioning

confidence: 60%

Three‐dimensional Model of the Structure and Evolution of Coronal Mass Ejections

Tokman

Bellan

2002

ApJ

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We present a new three-dimensional magnetohydrodynamic (MHD) model that describes the evolution of coronal magnetic arcades in response to photospheric Ñows. The dynamics of the system is discussed, and it is shown that the model reproduces a number of features characteristic of coronal mass ejection (CME) observations. In particular, we propose explanations for the three-part structure of CMEs observed at the solar limb and the formation and evolution of sigmoids and overlaying arcades. The model includes the e †ects of Ðnite resistivity in the system and morphological changes induced by reconnection are studied. Reconnection is found to prevent the formation of highly twisted magnetic structures if the magnitude of photospheric velocity is close to the observed values. In addition, we suggest a novel explanation for the splitting of the CMEÏs core prominence material observed in some eruptions. The distinguishing features of the model are the novel numerical methods used to evolve the MHD system and the formulation of the boundary conditions. The sti †ness of the resistive MHD equations constitutes a major difficulty for numerical simulations. Calculations in our model are performed using recently introduced exponential propagation techniques that allow efficient integration of the equations with time steps far exceeding the CFL bound that constrains explicit schemes.

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Section: Model Descriptionmentioning

confidence: 60%

Three‐dimensional Model of the Structure and Evolution of Coronal Mass Ejections

Tokman

Bellan

2002

ApJ

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“…The combination of low ␤, high Lundquist number, and experimental time larger than the Alfvén time (ϳ0.05 s using an estimated Alfvén velocity of 2ϫ10 6 m/s and assuming a typical length scale of 0.1 m͒ but shorter than the resistive diffusive time (ϳ300 s) produces a reasonable simulation of the solar parameter regime. 1,16 The four-electrode plasma gun permits a multitude of different operating conditions because the polarity of each of the four bias field coils can be set independently and because the gas can be selectively injected through any combination of bias field foot-points. If the bias field for a lab prominence is oriented such that this field is parallel to the prominence current, then a right-handed ͑positive helicity͒ prominence is created whereas if the bias field is anti-parallel to the prominence current, a left-handed ͑negative helicity͒ prominence is created.…”

Section: Methodsmentioning

confidence: 99%

Co- and counter-helicity interaction between two adjacent laboratory prominences

2004

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The interaction between two side-by-side solar prominence-like plasmas has been studied using a four-electrode magnetized plasma source that can impose a wide variety of surface boundary conditions. When the source is arranged to create two prominences with the same helicity ͑co-helicity͒, it is observed that helicity transfer from one prominence to the other causes the receiving prominence to erupt sooner and faster than the transmitting prominence. When the source is arranged to create two prominences with opposite helicity ͑counter-helicity͒, it is observed that upon merging, prominences wrap around each other to form closely spaced, writhing turns of plasma. This is followed by appearance of a distinct bright region in the middle and order of magnitude higher emission of soft x rays. The four-electrode device has also been used to change the angle of the neutral line and so form more pronounced S-shapes.

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“…After breakdown, plasma arches form, analogous to solar prominence loops [18]. These arches are distributed toroidally, reminiscent of spider legs, with each 'leg' linking a gas nozzle on the disk to a corresponding nozzle on the annulus (Fig.…”

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confidence: 99%

Dynamic and Stagnating Plasma Flow Leading to Magnetic-Flux-Tube Collimation

2005

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Highly collimated, plasma-filled magnetic flux tubes are frequently observed on galactic, stellar and laboratory scales. We propose that a single, universal magnetohydrodynamic pumping process explains why such collimated, plasma-filled magnetic flux tubes are ubiquitous. Experimental evidence from carefully diagnosed laboratory simulations of astrophysical jets confirms this assertion and is reported here. The magnetohydrodynamic process pumps plasma into a magnetic flux tube and the stagnation of the resulting flow causes this flux tube to become collimated.The extreme collimation of astrophysical jets [1,2,3] and the solar corona heating mechanism [4] are two seemingly unrelated astrophysical mysteries, yet both involve collimation of magnetic flux tubes. Astrophysical observations [2,3] and simulations [1,5] indicate that bipolar plasma outflows (jets) are natural [1,6] features of young stellar objects, black holes, active galactic nuclei and even aspherical planetary nebula [7]. Although it has long been presumed [8,9] that astrophysical jets are magnetohydrodynamically driven, the standard models do not agree on a single collimation process. A similar issue exists in solar physics: solar spicules [10], prominences [11,12] and coronal loops [13] are considered to be plasma-filled filamentary magnetic flux tubes; coronal heating models [14,15] then invoke magnetic reconnection and plasma flow within such filamentary loops. However, the models explain neither the origin of the observed flows nor the extreme collimation (filamentary nature) of the observed structures.We propose that the collimation of any, initially flared, current-carrying magnetic flux tube is due to the following process [16]: a magnetohydrodynamic (MHD) force resulting from the flared current profile drives axial plasma flows along the flux tube; the flows convect frozen-in magnetic flux from strong magnetic field regions to weak magnetic field regions; flow stagnation then piles up this embedded magnetic flux, increasing the local magnetic field and collimating the flux tube via the pinch effect. Thus, the flux tube fills with ingested plasma and simultaneously becomes collimated. This paper presents direct experimental evidence for this process. We use ultra-high-speed imaging and Doppler measurements of the fast plasma flows, combined with direct density measurements before and after the filling of the flux tube.Our experimental setup [17] simulates magneticallydriven astrophysical jets at the laboratory scale by imposing boundary conditions analogous to astrophysical jet boundary conditions (Fig. 1): a disk (cathode) representing a central object such as a star, is coaxial and co-planar with an annulus (anode) representing an accretion disk. A vacuum poloidal magnetic field produced by an external coil links these two electrodes, mimicking a poloidal magnetic field threading the accretion disk. A radial electric field applied across the gap between the FIG. 1: (log color) Typical plasma discharge sequence (#6577, 2 million fps, 40 ns/...

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Laboratory simulations of solar prominence eruptions

Cited by 42 publications

References 24 publications

Three‐dimensional Model of the Structure and Evolution of Coronal Mass Ejections

Three‐dimensional Model of the Structure and Evolution of Coronal Mass Ejections

Co- and counter-helicity interaction between two adjacent laboratory prominences

Dynamic and Stagnating Plasma Flow Leading to Magnetic-Flux-Tube Collimation

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