Three‐Dimensional Global Hybrid Simulations of High Latitude Magnetopause Reconnection and Flux Ropes during the Northward IMF

<p>Flux ropes are ubiquitous at Earth&#8217;s magnetopause and play important roles in energy transport between the solar wind and Earth&#8217;s magnetosphere. In this paper, structure and coalescence of the magnetopause flux ropes formed by multiple X line reconnection in cases with different southward interplanetary magnetic field (IMF) clock angles are investigated by using three-dimensional global hybrid simulations. As the IMF clock angle decreases from 180&#176;, the axial direction of the flux ropes becomes tilted relative to the equatorial plane, the length of the flux ropes gradually increases, and core field within flux ropes is formed by the increase in the guide field. The flux ropes are formed mostly near the subsolar point and then move poleward towards cusps. The flux ropes can eventually enter the cusps, during which their helical structure collapses, their core field weakens gradually, and their axial length decreases. When the IMF clock angle is large (i.e., the IMF is predominantly southward), the flux ropes can coalesce and form new ones with larger diameter. The coalescence between flux ropes can occur both near the subsolar point when they are newly formed and away from the subsolar point (e.g., in the southern hemisphere) when they move towards cusps. However, when the IMF clock angle is small (&#8804; 135&#176; ), we do not find coalescence between flux ropes.</p>

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Ion‐scale secondary flux ropes generated by magnetopause reconnection as resolved by MMS

Geophysical Research Letters ◽

10.1002/2016gl068747 ◽

2016 ◽

Vol 43 (10) ◽

pp. 4716-4724 ◽

Cited By ~ 58

Author(s):

J. P. Eastwood ◽

T. D. Phan ◽

P. A. Cassak ◽

D. J. Gershman ◽

C. Haggerty ◽

...

Keyword(s):

Flux Ropes ◽

Magnetopause Reconnection

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A three-dimensional model study of long-term mid-high latitude lower stratosphere ozone changes

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-3-1081-2003 ◽

2003 ◽

Vol 3 (1) ◽

pp. 1081-1107 ◽

Cited By ~ 1

Author(s):

M. P. Chipperfield

Keyword(s):

High Latitude ◽

Lower Stratosphere ◽

Transport Model ◽

Three Dimensional ◽

Horizontal Resolution ◽

Chemical Transport Model ◽

Three Dimensional Model ◽

Detailed Chemistry ◽

Basic Model ◽

Column Ozone

Abstract. We have used a 3D off-line chemical transport model (CTM) to study the causes of the observed changes in ozone in the mid-high latitude lower stratosphere from 1979–1998. The model was forced by European Centre for Medium Range Weather Forecasts (ECMWF) analyses and contains a detailed chemistry scheme. A series of model runs were performed at a horizontal resolution of 7.5°×7.5° and covered the domain from about 12 km to 30 km. The basic model performs well in reproducing the decadal evolution of the springtime depletion in the northern hemisphere (NH) and southern hemisphere (SH) high latitudes in the 1980s and early 1990s. After about 1994 the modelled interannual variability does not match the observations as well, which is probably due in part to changes in the operational ECMWF analyses – which places limits on using this dataset to diagnose dynamical trends. For mid-latitudes (35°–60°) the basic model reproduces the observed column ozone decreases from 1980 until the early 1990s. Model experiments show that the halogen trends appear to dominate this modelled decrease and of this around 30–50% is due to high-latitude processing on polar stratospheric clouds (PSCs). Dynamically induced ozone variations in the model correlate with observations over the timescale of a few years. Large discrepancies between the modelled and observed variations in the mid 1980s and mid 1990s can be largely resolved by assuming that the 11-year solar cycle (not explicitly included in the 3D model) causes a 2% (min-max) change in mid-latitude column ozone.

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Hybrid-Vlasov modelling of three-dimensional dayside magnetopause reconnection

10.5194/egusphere-egu21-13054 ◽

2021 ◽

Author(s):

Yann Pfau-Kempf ◽

Minna Palmroth ◽

Andreas Johlander ◽

Lucile Turc ◽

Markku Alho ◽

...

Keyword(s):

Magnetic Field ◽

Magnetic Reconnection ◽

Three Dimensional ◽

Meridional Plane ◽

Kinetic Behavior ◽

Dayside Magnetopause ◽

Field Junction ◽

First Time ◽

Kinetic Instabilities ◽

Magnetopause Reconnection

<p>Dayside magnetic reconnection at the magnetopause, which is a major driver of space weather, is studied for the first time in a three-dimensional (3D) realistic setup using the Vlasiator hybrid-Vlasov kinetic model. A noon&#8211;midnight meridional plane simulation is extended in the dawn&#8211;dusk direction to cover 7 Earth radii. The southward interplanetary magnetic field causes magnetic reconnection to occur at the subsolar magnetopause. Perturbations arising from kinetic instabilities in the magnetosheath appear to modulate the reconnection. Its characteristics are consistent with multiple, bursty, and patchy magnetopause reconnection. It is shown that the kinetic behavior of the plasma, as simulated by the model, has consequences on the applicability of methods such as the four-field junction to identify and analyse magnetic reconnection in 3D kinetic simulations.</p>

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Three-dimensional CFD modeling approach to approximate air pollution conditions in high-latitude open-pit mines

WIT Transactions on The Built Environment - Sustainable Development ◽

10.2495/sd150652 ◽

2015 ◽

pp. 741-753 ◽

Cited By ~ 1

Author(s):

T. Bhowmick ◽

S. Bandopadhyay ◽

T. Ghosh

Keyword(s):

Air Pollution ◽

High Latitude ◽

Three Dimensional ◽

Open Pit ◽

Cfd Modeling ◽

Open Pit Mines ◽

Modeling Approach

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Solar wind control of plasma number density in the near-Earth plasma sheet: three-dimensional structure

Annales Geophysicae ◽

10.5194/angeo-26-4031-2008 ◽

2008 ◽

Vol 26 (12) ◽

pp. 4031-4049 ◽

Cited By ~ 18

Author(s):

D. Nagata ◽

S. Machida ◽

S. Ohtani ◽

Y. Saito ◽

T. Mukai

Keyword(s):

Solar Wind ◽

Density Dependence ◽

High Latitude ◽

Plasma Sheet ◽

Strong Dependence ◽

Three Dimensional ◽

Dimensional Structure ◽

Lower Latitude ◽

Number Density ◽

Three Dimensional Structure

Abstract. The plasma number density in the near-Earth plasma sheet depends on the solar wind number density and the north-south component of interplanetary magnetic field (IMF Bz) with time lag and duration of several hours. We examined the three-dimensional structure of such dependences by fitting observations of plasma sheet and solar wind to an empirical model equation. Analyses were conducted separately for northward and southward IMF conditions. Effects of solar wind speed and IMF orientation were also examined by further subdivision of the dataset. Based on obtained results, we discuss (i) the relative contribution of the ionosphere and solar wind to plasma sheet mass supply, (ii) the entry mechanisms for magnetosheath particles, and (iii) the plasma transport in the plasma sheet. We found that solar wind number density dependence is weaker and IMF Bz dependence is stronger for faster solar wind with southward IMF, which suggests the contribution of ionospheric particles. Further from the Earth, different interplanetary conditions result in different structures of solar wind dependence, which indicate different solar wind entry mechanisms: (1) southward IMF results in a strong dependence on solar wind number density in the flank high-latitude region, (2) slow solar wind with northward IMF leads to lower-latitude peaks of solar wind number density dependence in the flank region, (3) fast solar wind with northward IMF results in a strong dependence on solar wind number density at the down-tail dusk flank equator, and (4) solar wind number density dependence is stronger in the downstream of quasi-parallel bow shock. These features are attributable to (1) low-latitude dayside reconnection entry, (2) high-latitude dayside reconnection entry, (3) entry due to decay of Kelvin-Helmholtz vortices, and (4) diffusive entry mediated by kinetic Alfven waves, respectively. Effect of IMF Bz and its time lags show plasma sheet reconfiguration associated with enhanced convective transport under southward IMF. Duration of IMF Bz effect under northward IMF is interpreted in terms of turbulent diffusive transport.

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