1887
banner image
No data available.
Please log in to see this content.
You have no subscription access to this content.
No metrics data to plot.
The attempt to load metrics for this article has failed.
The attempt to plot a graph for these metrics has failed.
The effects of strong temperature anisotropy on the kinetic structure of collisionless slow shocks and reconnection exhausts. I. Particle-in-cell simulations
Rent:
Rent this article for
USD
10.1063/1.3601760
/content/aip/journal/pop/18/6/10.1063/1.3601760
http://aip.metastore.ingenta.com/content/aip/journal/pop/18/6/10.1063/1.3601760

Figures

Image of FIG. 1.
FIG. 1.

(Color online) The exhaust from steady reconnection in a PIC simulation. Panel (a): The out-of-plane electron current density J ey ; Panel (b): , where positive values have been set to 0. The colored region is firehose unstable; Panel (c): The magnitude of B x showing the development of 2-D turbulence; Panel (d): A cut of ɛ at x/d i  = –35 (the vertical line in (b)). The horizontal lines demarcate ɛ = 0.25 and ɛ = 0.

Image of FIG. 2.
FIG. 2.

(Color online) The evolution of a system with θ BN  = 75° (Run f). Panel (a): The evolution of B from time 0–200/Ω ci . A pair of fast rarefactions (FR) propagate out from the symmetry line, followed by a pair of slow shocks (SS). Each curve has been shifted so that it intersects the vertical axis at the given time. The time between the yellow curves is 100/Ω ci ; Panel (b): The predicted FR and switch-off slow shock (SSS) from ideal MHD theory; Panel (c): The same as (a) but with the vertical axis measuring B; Panel (d): The evolution of B z from time 0–200/Ω ci .

Image of FIG. 3.
FIG. 3.

(Color online) Parameters from the run with θ BN  = 75° (Run f) at time 200/Ω ci . Panel (a): Temperature anisotropy ɛ and x-direction heat flux Q x ; Panel (b): Magnetic field components; Panel (c): Parallel and perpendicular temperatures (the off-diagonal components T ixy , T ixz , T iyz are plotted together in green, denoted as T off, and are small); Panel (d): Total plasma pressure components and P x  + B 2/2μ 0. Panel (e): The plasma β and local θ BN  = cos–1(B x /B); Panel (f): Plasma density. The dotted curves in each panel are the predicted magnitude and position of the switch-off slow shocks (SSS) from isotropic MHD for B z in (b), T in (c), P in (d), β in (e), and n in (f).

Image of FIG. 4.
FIG. 4.

(Color online) The phase space of the run with θ BN  = 75° (Run f) at time 200/Ω ci . From top to bottom the left column shows the ion distribution in: V z x space, where the backstreaming ions from the discontinuities are clearly seen; V y x space; V x x space. The right column is the electron distribution in V z x space, V y x space and V x x space. The white dashed lines indicate the locations of the velocity distributions shown in Fig. 5. The color bar is normalized to the maximum value in each panel.

Image of FIG. 5.
FIG. 5.

(Color online) The ion velocity distributions measured at locations 409.1–410.1d i , 415–416d i and 430–431d i of Fig. 4 (the white dashed lines). From top to bottom are V z V x , V z V y and V x V y distributions. The distributions are color coded and the white contours help identify different ion parcels. The local magnetic field is denoted by blue arrowed lines beginning at origin. The axis scales, when cut by a factor of 2, also measure the magnitude of the field. Ions that stream along the magnetic field are clearly seen at these locations.

Image of FIG. 6.
FIG. 6.

(Color online) From top to bottom are runs with θ BN  = 30° (Run a) at 100/Ω ci , 45° (Run b) at 200/Ω ci , 52° (Run c) at 100/Ω ci , 60° (Run d) at 250/Ω ci , 75° (Run f) at 400/Ω ci , and 83° (Run k) at 700/Ω ci . The first column shows the temperature anisotropy, and the second column the magnetic field components as a function of x. The third column displays hodograms taken from the right half of the simulation domains. The dotted curves in the second column are the predicted magnitudes and positions of switch-off slow shocks (SSS) and fast rarefactions (FR) from isotropic MHD theory for Bz.

Image of FIG. 7.
FIG. 7.

(Color online) Evolution of ɛ for the case with θ BN  = 60° (Run d) for equally spaced times between 100 – 500/Ω ci from lighter grey to darker grey in (a), the θ BN  = 75° case (Run f) for time 100 – 500/Ω ci in (b), and the θ BN  = 83° case (Run k) for time 100 – 700/Ω ci in (c). The bottom is a plot of B x for the θ BN  = 83° case at time 700/Ω ci showing the 2-D turbulence that develops.

Image of FIG. 8.
FIG. 8.

(Color online) The ɛ distributions of runs θ BN  = 60° (Run d) at 500/Ω ci , 75° (Run f) at 200/Ω ci , 83° (Run k) at 700/Ω ci . (The 83° case is shifted to the right by 204.8d i .)

Image of FIG. 9.
FIG. 9.

(Color online) Panel (a): The evolution of ɛ, B z and B y for equally spaced times between 50–500/Ω ci (from left to right) in the θ BN  = 75°, w i  = 10d i case (Run g). The downstream larger-scale rotational wave breaks into waves of wavelength ∼ 6d i . Panel (b): A blowup of the downstream B y at time 450/Ω ci .

Image of FIG. 10.
FIG. 10.

(Color online) The evolution of B y , B z and B for equally spaced times between 0–100/Ω ci . The red curve indicates the time 100/Ω ci . Panel (a): Run 1 with both initial streaming ions and modulated rotational parent wave. Panel (b): The same as panel (a) without the initial spatial modulation (Run 3). Panel (c): The same as panel (a) without initial beams (Run 5). Panel (d): The same as panel (c) without initial polarization (Run 6).

Image of FIG. 11.
FIG. 11.

The evolution of for equally spaced times between 0–100/Ω ci (from lighter grey to darker grey) of Run 1 (Fig. 10(a)). The temperature anisotropy of the ions is reduced, which indicates particle scattering is taking place.

Tables

Generic image for table
Table I.

Parameters and results of shock simulations.

Generic image for table
Table II.

Parameters and results.

Loading

Article metrics loading...

/content/aip/journal/pop/18/6/10.1063/1.3601760
2011-06-28
2014-04-20
Loading

Full text loading...

This is a required field
Please enter a valid email address
752b84549af89a08dbdd7fdb8b9568b5 journal.articlezxybnytfddd
Scitation: The effects of strong temperature anisotropy on the kinetic structure of collisionless slow shocks and reconnection exhausts. I. Particle-in-cell simulations
http://aip.metastore.ingenta.com/content/aip/journal/pop/18/6/10.1063/1.3601760
10.1063/1.3601760
SEARCH_EXPAND_ITEM