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Spontaneous hot flow anomalies at Mars and Venus
Zhang, Tielong; Futaana, Yoshifumi; Persson, Moa +8 more
We report the first observations of Spontaneous Hot Flow Anomalies (SHFAs) at Venus and Mars, demonstrating their existence in the foreshocks of other planets beyond Earth. Using data from the ESA Venus Express and the NASA Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft, we present magnetic and plasma observations from events at both pl…
Asymmetries in the Magnetosheath Field Draping on Venus' Nightside
Volwerk, M.; Bertucci, C.; Delva, M. +1 more
Draping features of the interplanetary magnetic field around nonmagnetic bodies, especially Venus, have been studied in detail in numerical simulations and also from observations. Existing analytical and numerical work for nonperpendicular interplanetary magnetic field and solar wind velocity direction show a kink in the draped fieldlines in the n…
Characteristics of ionospheric flux rope at the terminator observed by Venus Express
Zhang, T. L.; Chen, Y. Q.; Wang, G. Q. +1 more
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 prese…
Statistical study of low-frequency magnetic field fluctuations near Venus during the solar cycle
Zhang, T. L.; Wang, G. Q.; Xiao, S. D.
We statistically investigate the solar cycle dependence of the magnetic field fluctuations in the frequency range 30-300 MHz based on Venus Express data. We present the spatial distributions of fluctuation properties during three typical periods of the solar cycle, and a comparative study is also performed. With the increase of solar activity, the…
A study of ionopause perturbation and associated boundary wave formation at Venus
Zhang, Tielong; Collinson, Glyn A.; Chong, Ghai Siung +3 more
Magnetometer and electron spectrometer data from Venus Express (VEX) are used to investigate the occurrence of boundary wave phenomenon occurring in the vicinity of the Venusian terminator. On 26 June 2006, VEX data show the ionosphere to be unmagnetized (≈0 nT), a common observation usually expected during solar maximum. This results in the respe…
Validation of single spacecraft methods for collisionless shock velocity estimation
Pope, Simon A.; Walker, Simon N.; Collinson, Glyn +1 more
The velocity of a collisionless shock (CS) is an important parameter in the determination of the spatial scales of the shock. The spatial scales of the shock determine the processes that guide the energy dissipation, which is related to the nature of the shock. During the pre-ISEE era, estimations of relative shock-spacecraft velocity (VSh