Electric field penetration into Earth's ionosphere: a brief review for 2000-2013

Electric field penetration is a consequence of solar wind interaction with planetary magnetosphere and/or ionosphere. For both Earth with intrinsic magnetosphere and Mars/Venus without intrinsic magnetosphere, the penetration electric field causes various kinds of global and local electrodynamic response of the ionosphere to the solar wind electric field, especially the plasma motion in the ionosphere. Within the first 14 years of the twenty-first century, the cause and effect of the electric field penetration on Earth has been investigated extensively and understood more deeply. Here we review the progress acquired on the patterns and drivers of the penetration electric field, and its influences on the plasma distribution and the equatorial spread F in the mid- and low-latitude ionosphere. From the perspective of comparative study, we also shortly introduce the new results for Mars. What has become clear is that our understanding of electric field penetration has been significantly improved, but ultimately the crucial details of the global picture still remain unknown. Looking forward to the future research of the electric field penetration in Earth's ionosphere, the breakthrough relies on new instruments built up at different longitudes to improve the global coverage of the observation. An integrated network of instrument is necessary to reveal the longitude and local-time dependence of the electric field penetration and shed new light on the physical details of the global ionospheric processes driven by the electric field penetration.