scholarly journals Regimes of magnetic reconnection in colliding laser-produced magnetized plasma bubbles

2018 ◽  
Vol 25 (9) ◽  
pp. 093105 ◽  
Author(s):  
K. V. Lezhnin ◽  
W. Fox ◽  
J. Matteucci ◽  
D. B. Schaeffer ◽  
A. Bhattacharjee ◽  
...  
Keyword(s):  
Magnetic Reconnection ◽  
Magnetized Plasma ◽  
Plasma Bubbles

scholarly journals Fast Magnetic Reconnection in Laser-Produced Plasma Bubbles

2011 ◽  
Vol 106 (21) ◽  
Author(s):  
W. Fox ◽  
A. Bhattacharjee ◽  
K. Germaschewski
Keyword(s):  
Magnetic Reconnection ◽  
Plasma Bubbles ◽  
Laser Produced Plasma

Electron Magnetohydrodynamics Magnetic Reconnection Experiment on Keda Linear Magnetized Plasma Device

2019 ◽  
Vol 36 (1) ◽  
pp. 015201
Author(s):  
Feibin Fan ◽  
Jinlin Xie ◽  
Qiaofeng Zhang ◽  
Longlong Sang ◽  
Weixing Ding
Keyword(s):  
Magnetic Reconnection ◽  
Magnetized Plasma ◽  
Plasma Device

scholarly journals Radiation and Polarization Signatures from Magnetic Reconnection in Relativistic Jets. II. Connection with γ-Rays

2022 ◽  
Vol 924 (2) ◽  
pp. 90
Author(s):  
Haocheng Zhang ◽  
Xiaocan Li ◽  
Dimitrios Giannios ◽  
Fan Guo ◽  
Hannes Thiersen ◽  
...  
Keyword(s):  
Magnetic Reconnection ◽  
Magnetic Energy ◽  
High Energy ◽  
Magnetized Plasma ◽  
Emission Region ◽  
Polarization Angle ◽  
Optical Polarization ◽  
Particle Distributions ◽  
Particle In Cell ◽  
Very High Energy

Abstract It is commonly believed that blazar jets are relativistic magnetized plasma outflows from supermassive black holes. One key question is how the jets dissipate magnetic energy to accelerate particles and drive powerful multiwavelength flares. Relativistic magnetic reconnection has been proposed as the primary plasma physical process in the blazar emission region. Recent numerical simulations have shown strong acceleration of nonthermal particles that may lead to multiwavelength flares. Nevertheless, previous works have not directly evaluated γ-ray signatures from first-principles simulations. In this paper, we employ combined particle-in-cell and polarized radiation transfer simulations to study multiwavelength radiation and optical polarization signatures under the leptonic scenario from relativistic magnetic reconnection. We find harder-when-brighter trends in optical and Fermi-LAT γ-ray bands as well as closely correlated optical and γ-ray flares. The swings in optical polarization angle are also accompanied by γ-ray flares with trivial time delays. Intriguingly, we find highly variable synchrotron self-Compton signatures due to inhomogeneous particle distributions during plasmoid mergers. This feature may result in fast γ-ray flares or orphan γ-ray flares under the leptonic scenario, complementary to the frequently considered minijet scenario. It may also imply neutrino emission with low secondary synchrotron flux under the hadronic scenario, if plasmoid mergers can accelerate protons to very high energy.

scholarly journals Avalanches of Magnetic Reconnection

1993 ◽  
Vol 141 ◽  
pp. 112-114
Author(s):  
Edward T. Lu
Keyword(s):  
Magnetic Field ◽  
Magnetic Reconnection ◽  
Energy Release ◽  
Power Law ◽  
Magnetic Energy ◽  
Magnetized Plasma ◽  
Release Process ◽  
3 Dimensional ◽  
Convective Motions ◽  
The Magnetic Field

AbstractActive region coronal magnetic fields are expected to be in a twisted tangled state due to photospheric convective motions. These motions can drive the magnetic field to a statistically steady state where energy is released impulsively (Lu and Hamilton 1991). These relaxation events in the magnetic field can be interpreted as avalanches of many small reconnection events. We argue that the frequency distribution of these magnetic reconnection avalanches must be a power law. Furthermore, we calculate the expected distributions in a simple model of magnetic energy release events in a 3-dimensional complex magnetized plasma, and compare these to the distributions of solar flares. These distributions are found to match the observed power law distributions of solar flare energies, peak fluxes, and durations. This model implies that the energy-release process is fundamentally the same for flares of all sizes. Observational predictions of this model are discussed.

Energetic electron generation by magnetic reconnection in laboratory laser-plasma interactions

2012 ◽  
Vol 78 (4) ◽  
pp. 497-500 ◽  
Author(s):  
Q.-L. DONG ◽  
D.-W. YUAN ◽  
S.-J. WANG ◽  
Y. T. LI ◽  
X. LIU ◽  
...  
Keyword(s):  
Laser Pulse ◽  
Magnetic Reconnection ◽  
Current Sheet ◽  
Laser Plasma ◽  
Energetic Electron ◽  
Energetic Electrons ◽  
Accelerated Electrons ◽  
Laser Plasma Interactions ◽  
Plasma Bubbles ◽  
Electron Generation

AbstractThe magnetic reconnection (MR) configuration was constructed by using two approaching laser-produced plasma bubbles. The characteristics of the MR current sheet were investigated. The driving energy of the laser pulse affects the type of the current sheet. The experiments present “Y-type” and “X-type” current sheets for larger and smaller driving energy, respectively. The energetic electrons were found to be well-collimated. The formation and ejection of plasmoid from the “Y-type” current sheet was expected to enhance the number of accelerated electrons.

Structure functions analysis of sub-ion scale turbulent fluctuations and dissipation range in a magnetized plasma

2021 ◽  
Author(s):  
Giuseppe Arrò ◽  
Francesco Califano ◽  
Giovanni Lapenta
Keyword(s):  
Magnetic Field ◽  
Magnetic Reconnection ◽  
Plasma Turbulence ◽  
Structure Functions ◽  
Magnetized Plasma ◽  
Small Scale ◽  
Turbulent Fluctuations ◽  
The Magnetic Field ◽  
Turbulent Cascade ◽  
Dissipation Range

<p>Turbulence in collisionless magnetized plasmas is a complex multi-scale process involving many decades of scales ranging from large magnetohydrodynamic (MHD) scales down to small ion and electron kinetic scales, associated with different physical regimes. It is well know that the MHD turbulent cascade is driven by the nonlinear interaction of low-frequency Alfvén waves but, on the other hand, the properties of plasma turbulence at sub-ion scales are not yet fully understood. In addition to a great variety of relatively high frequency modes such as kinetic Alfvén waves and whistler waves, magnetic reconnection has been suggested to be a key element in the development of kinetic scale turbulence because it allows for energy to be transferred from large scales directly into sub-ion scales through currents sheets disruption. In this context, an unusual reconnection mechanism driven exclusively by the electrons (with ions being demagnetized), called "electron-only reconnection", has been recently observed for the first time in the Earth’s magnetosheath and its role in plasma turbulence is still a matter of great debate. <br><br>Using 2D-3V hybrid Vlasov-Maxwell (HVM) simulations of freely decaying plasma turbulence, we investigate and compare the properties of the turbulence associated with standard ion-coupled reconnection and of the turbulence associated with electron-only reconnection [Califano et al., 2018]. By analyzing the structure functions of the turbulent magnetic field and ion fluid velocity fluctuations, we find that the turbulence associated with electron-only reconnection shows the same statistical features as the turbulence associated with standard ion-coupled reconnection and no peculiar signature related to electron-only reconnection is found in the turbulence statistics. This result suggests that the properties of the turbulent cascade in a magnetized plasma are independent of the specific mechanism associated with magnetic reconnection but depend only on the coupling between the magnetic field and the different particle species present in the system. Finally, the properties of the magnetic field dissipation range are discussed as well and we claim that its formation, and thus the dissipation of magnetic energy, is driven only by the small scale electron dynamics since ions are demagnetized in this range [Arró et al., 2020].<br><br>This work has received funding from the European Union Horizon 2020 research and innovation programme under grant agreement No 776262 (AIDA, www.aida-space.eu).<br><br>References:<br><br>G. Arró, F. Califano, and G. Lapenta. Statistical properties of turbulent fluctuations associated with electron-only magnetic reconnection. , 642:A45, Oct. 2020. doi: 10.1051/0004-6361/202038696.<br><br>F. Califano, S. S. Cerri, M. Faganello, D. Laveder, M. Sisti, and M. W. Kunz. Electron-only magnetic reconnection in plasma turbulence. arXiv e-prints, art. arXiv:1810.03957, Oct. 2018.</p>

scholarly journals Taylor State Merging at SSX: Experiment and Simulation

Plasma ◽  
2020 ◽  
Vol 3 (1) ◽  
pp. 27-37
Author(s):  
Michael Brown ◽  
Kaitlin Gelber ◽  
Matiwos Mebratu
Keyword(s):  
Magnetic Reconnection ◽  
Magnetized Plasma ◽  
The Other ◽  
Inertial Fusion ◽  
Ion Heating ◽  
Left Handed ◽  
Suitable Target ◽  
Magnetohydrodynamic Simulations ◽  
Plasma Guns ◽  
Warm State

We describe experiments and simulations of dynamical merging with two Taylor state plasmas in a Swarthmore Spheromak Experiment (SSX) device. Taylor states are formed by magnetized plasma guns at opposite ends of the device. We performed experiments with Taylor states of both senses of magnetic helicity (right-handed twist or left-handed twist). We present results of both counter-helicity merging (one side left-handed, the other right-handed) and co-helicity merging (both sides left-handed). Experiments show significant ion heating, consistent with magnetic reconnection. We suggest that the merged, warm state could be a suitable target for future magneto-inertial fusion experiments. Magnetohydrodynamic simulations of these experiments reveal the structure of the final relaxed, merged state.

scholarly journals The Early Evolution of Solar Flaring Plasma Loops

Universe ◽  
2021 ◽  
Vol 7 (10) ◽  
pp. 378
Author(s):  
Baolin Tan
Keyword(s):  
Magnetic Fields ◽  
Magnetic Reconnection ◽  
Active Regions ◽  
Critical Value ◽  
Early Evolution ◽  
Magnetized Plasma ◽  
Solar Plasma ◽  
Whole Process ◽  
Weak Magnetic Fields ◽  
Plasma Loop

Plasma loops are the elementary structures of solar flaring active regions and dominate the whole process of flaring eruptions. Standard flare models explain evolution and eruption after magnetic reconnection around the hot cusp-structure above the top of plasma loops very well; however, the early evolution of plasma loops before the onset of magnetic reconnection is poorly understood. Considering that magnetic gradients are ubiquitous in solar plasma loops, this work applies the magnetic-gradient pumping (MGP) mechanism to study the early evolution of flaring plasma loops. The results indicate that early evolution depends on the magnetic field distribution and the geometry of the plasma loops, which dominate the balance between the accumulation and dissipation of the energy around loop tops. Driven by MGP process, both of the density and temperature as well as the plasma β value around the looptop will increase in the early phase of the plasma loop’s evolution. In fact, the solar plasma loops will have two distinct evolutionary results: low, initially dense plasma loops with relatively strong magnetic fields tend to be stable for their maximum β value, which is always smaller than the critical value β<βc, while the higher, initially diluted solar plasma loops with relatively weak magnetic fields tend to be unstable for their β values, exceeding the critical value β>βc at a time of about one hour after the formation of the solar-magnetized plasma loop. The latter may produce ballooning instability and may finally trigger the following magnetic reconnection and eruptions. These physical scenarios may provide us with a new viewpoint to understand the nature and origin of solar flares.

scholarly journals Statistical properties of turbulent fluctuations associated with electron-only magnetic reconnection

2020 ◽  
Vol 642 ◽  
pp. A45
Author(s):  
G. Arró ◽  
F. Califano ◽  
G. Lapenta
Keyword(s):  
Magnetic Field ◽  
Magnetic Reconnection ◽  
Fluid Velocity ◽  
Turbulent Energy ◽  
Plasma Turbulence ◽  
Statistical Properties ◽  
Energy Cascade ◽  
Magnetized Plasma ◽  
Field Energy ◽  
Turbulent Fluctuations

Context. Recent satellite measurements in the turbulent magnetosheath of Earth have given evidence of an unusual reconnection mechanism that is driven exclusively by electrons. This newly observed process was called electron-only reconnection, and its interplay with plasma turbulence is a matter of great debate. Aims. By using 2D-3V hybrid Vlasov–Maxwell simulations of freely decaying plasma turbulence, we study the role of electron-only reconnection in the development of plasma turbulence. In particular, we search for possible differences with respect to the turbulence associated with standard ion-coupled reconnection. Methods. We analyzed the structure functions of the turbulent magnetic field and ion fluid velocity fluctuations to characterize the structure and the intermittency properties of the turbulent energy cascade. Results. We find that the statistical properties of turbulent fluctuations associated with electron-only reconnection are consistent with those of turbulent fluctuations associated with standard ion-coupled reconnection, and no peculiar signature related to electron-only reconnection is found in the turbulence statistics. This result suggests that the turbulent energy cascade in a collisionless magnetized plasma does not depend on the specific mechanism associated with magnetic reconnection. The properties of the dissipation range are discussed as well, and we claim that only electrons contribute to the dissipation of magnetic field energy at sub-ion scales.

A large rotating structure around AB Doradus A at VLBI scale

2019 ◽  
Vol 15 (S354) ◽  
pp. 189-194
Author(s):  
J. B. Climent ◽  
J. C. Guirado ◽  
R. Azulay ◽  
J. M. Marcaide
Keyword(s):  
Magnetic Reconnection ◽  
Main Sequence ◽  
Complex Structure ◽  
Main Sequence Star ◽  
Polar Cap ◽  
Vlbi Observations ◽  
Rotating Structure ◽  
Source Structure ◽  
Expected Position

AbstractWe report the results of three VLBI observations of the pre-main-sequence star AB Doradus A at 8.4 GHz. With almost three years between consecutive observations, we found a complex structure at the expected position of this star for all epochs. Maps at epochs 2007 and 2010 show a double core-halo morphology while the 2013 map reveals three emission peaks with separations between 5 and 18 stellar radii. Furthermore, all maps show a clear variation of the source structure within the observing time. We consider a number of hypothesis in order to explain such observations, mainly: magnetic reconnection in loops on the polar cap, a more general loop scenario and a close companion to AB Dor A.

Sign in / Sign up

Export Citation Format

Share Document