Is the flow‐aligned component of IMF really able to impact the magnetic field structure of Venusian magnetotail?

Rong, Zhaojin; Stenberg, G.; Wei, Yong; Chai, Lihui; Futaana, Yoshifumi; Barabash, S.; Wan, Weixing; Shen, C.

doi:10.1002/2016ja022413

“…Though the influences of IMF orientation were considered, the significance of the IMF magnitude was less discussed. Statistical studies from Venus Express data indicate that the coupling of IMF magnitude and orientation is important in the solar wind-Venus interaction (Chai et al 2014;Rong et al 2016). We could reasonably conclude that the effect of IMF orientation is not independent of the IMF magnitude.…”

Section: Introductionmentioning

confidence: 63%

The Dependence of the Venusian Induced Magnetosphere on the Interplanetary Magnetic Field: An MHD Study

Xu

¹

,

Xu

²

,

Zuo

³

et al. 2022

ApJ

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The influences of the interplanetary magnetic field (IMF) on the induced magnetosphere of Venus are investigated using a global multispecies magnetohydrodynamics (MHD) model. The simulation results show that the induced magnetosphere is controlled by the IMF components perpendicular to the solar wind velocity (B Y and B Z in the Venus Solar Orbital coordinate), rather than the IMF magnitude (∣B∣). With the increase of ( B Y 2 + B Z 2 ) 1 2 , the induced magnetosphere becomes stronger in field strength and thicker in spatial scale, and the bow shock locates farther from the planet. The parallel IMF component (B X ) has relatively small impacts on the magnetic barrier and the magnetotail, regardless of the various IMF magnitudes and orientations caused by different B X . The responses of the Venusian induced magnetosphere to the change of upstream IMF are also studied. The time-dependent MHD calculations show that the dayside magnetosphere responds quickly with a timescale of 10 s–10 minutes, depending on the considered magnetospheric region. For comparison, the timescale required for the adjustment of magnetotail as driven by an IMF rotation is derived to be ∼10–20 minutes.

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“…Previous studies on the induced magnetosphere of Venus have demonstrated that the polarity of IMF B x could modulate the draping of IMF around the planet (e.g., Delva et al, 2017;McComas et al, 1986;Rong et al, 2016).…”

Section: Influence Of Imf B Xmentioning

confidence: 99%

“…Previous studies on the induced magnetosphere of Venus have demonstrated that the polarity of IMF B x could modulate the draping of IMF around the planet (e.g., Delva et al., 2017; McComas et al., 1986; Rong et al., 2016). As sketched in Figures 8a–8b, under the presence of significant upstream IMF B x component, a kink‐like field structure named inverse polarity reversal layer (IPRL) (which a spacecraft would record when crossing it) (Romanelli et al., 2015) would appear at the boundary of an induced magnetosphere.…”

Section: Influence Of Solar Wind Conditionsmentioning

confidence: 99%

Three‐Dimensional Configuration of Induced Magnetic Fields Around Mars

Zhang

¹

,

Rong

²

,

Klinger

³

et al. 2022

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Using over 6 years of magnetic field data (October 2014–December 2020) collected by the Mars Atmosphere and Volatile EvolutioN, we conduct a statistical study on the three‐dimensional average magnetic field structure around Mars. We find that this magnetic field structure conforms to the pattern typical of an induced magnetosphere, that is, the interplanetary magnetic field (IMF) which is carried by the solar wind and which drapes, piles up, slips around the planet, and eventually forms a tail in the wake. The draped field lines from both hemispheres along the direction of the solar wind electric field (E) are directed toward the nightside magnetic equatorial plane, indicating that they are “sinking” toward the wake. These “sinking” field lines from the +E‐hemisphere (E pointing away from the plane) are more flared and dominant in the tail, while the field lines from the –E‐hemisphere (E pointing toward) are more stretched and “pinched” toward the plasma sheet. Such highly “pinched” field lines even form a loop over the pole of the –E‐hemisphere. The tail current sheet also shows an E‐asymmetry: the sheet is thicker with a stronger tailward trueJ→×trueB→ $\overrightarrow{J}\times \overrightarrow{B}$ force at +E‐flank, but much thinner and with a weaker trueJ→×trueB→ $\overrightarrow{J}\times \overrightarrow{B}$ (even turns sunward) at –E‐flank. Additionally, we find that IMF Bx can induce a kink‐like field structure at the boundary layer; the field strength is globally enhanced and the field lines flare less during high dynamic pressure.

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“…To understand the relationship or discern the discrepancy between reconnection outflow and background flow, one therefore should estimate the background flow velocities in the tail current sheet. We selected orbits from the entire life of VEx (April 2006 to December 2014) with a stable IMF condition, that is, we required that the average orientation of the IMF vector (averaged over 30 min) before the inbound and after the outbound crossing of the bow shock does not change more than 45° (as in Rong et al., 2014, 2016). Among these 401 orbits, we visually identified 193 magnetotail current sheet crossings when VEx is located inside the magnetotail (−3 < X VSO < 0 R V and

\sqrt{Y_{VSO}^{2} + Z_{VSO}^{2}}

< 1.3 R V ) and experiences a significant reversal of B x ,VSO (the difference of B x before and after the current sheet crossing should be larger than 10 nT).…”

Section: Statistics Of Ion Velocitymentioning

confidence: 99%

In Situ Observations of the Ion Diffusion Region in the Venusian Magnetotail

Gao

¹

,

Rong

²

,

Persson

³

et al. 2020

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Utilizing the in situ observations of the Analyzer of Space Plasmas and Energetic Atoms (ASPERA‐4) and the magnetometer (MAG) onboard Venus Express, we report evidence of crossing the ion diffusion region of magnetic reconnection. Evidence of magnetic reconnection is based on two cases recorded by Venus Express in the Venusian magnetotail. In both cases, the variations of the magnetic field components are consistent with the classical picture of crossing the ion diffusion region. Our evidence is also supported by observed ion flows whose directions and speeds agree with expected characteristics of reconnection outflow. The reconnection crossing cases demonstrate that magnetic reconnection can appear in both ± E‐hemispheres in the Venusian magnetotail. The Venusian magnetotail provides a unique space laboratory for the investigation of the reconnection process.

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Is the flow‐aligned component of IMF really able to impact the magnetic field structure of Venusian magnetotail?

Cited by 14 publications

References 36 publications

The Dependence of the Venusian Induced Magnetosphere on the Interplanetary Magnetic Field: An MHD Study

The Dependence of the Venusian Induced Magnetosphere on the Interplanetary Magnetic Field: An MHD Study

Three‐Dimensional Configuration of Induced Magnetic Fields Around Mars

In Situ Observations of the Ion Diffusion Region in the Venusian Magnetotail

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