Characteristics of ionospheric flux rope at the terminator observed by Venus Express

• Published in: Journal of geophysical research. Space physics Vol. 122; no. 8; pp. 8858 - 8867
• Main Authors: Chen, Y. Q., Zhang, T. L., Xiao, S. D., Wang, G. Q.
• Format: Journal Article
• Language: English
• Published: Washington Blackwell Publishing Ltd 01-08-2017
• Subjects: Altitude; Fluctuations; flux rope; Helicity; Horizontal orientation; Ionosphere; Low altitude; Magnetic flux; Solar activity; Solar maximum; terminator; Venus; Venus atmosphere; Venus Express (ESA); Venus ionosphere; Vertical orientation; Zenith
• ISSN: 2169-9380; 2169-9402
• DOI: 10.1002/2017JA023999

We investigate the characteristics of the magnetic flux rope in the Venusian ionosphere near the terminator observed by the Venus Express while previous works about flux rope by PVO are mainly in the subsolar region. The probability to observe the flux rope becomes larger as solar activity strengthens. A statistical work during solar maximum presents the following characteristics. (1) The flux ropes in the terminator region have a lower spatial occurrence compared with those in the subsolar region, and the spatial occurrence of the flux ropes is also getting smaller when altitude increases. (2) The scale size of the flux rope is larger in the terminator region than that in the subsolar region and becomes larger when altitude increases. (3) In the terminator region, the flux rope appears to have a quasi‐horizontal orientation but with some cases can be vertical at low altitude. (4) The flux ropes in high solar zenith angle regions are confirmed to have a lower helicity compared with those in low solar zenith angle regions.
Key Points
An overall statistic work about characteristics of the flux rope at the terminator
We find a less occurrence and a larger‐scale size of flux ropes in terminator region
The flux rope's orientation can be vertical at low altitude, and flux ropes in terminator region are found less twisted