空间物理学最新进展与展望

空间物理学是人类进入空间时代后迅速发展的一门新兴交叉学科,特别是进入新世纪后国内外都取得了辉煌的成就.本文简要介绍空间物理领域近年来取得的重要进展、重要成果、国内外发展趋势,以及未来发展的重点方向.

Foreword

It is now more than a decade since the twenty-first Chinese National Antarctic Research Expedition （21st CHINARE） reached the highest point of the Antarctic Ice Sheet on 18 January 2005, around the 20th anniversary of China＇s involvement in polar scientific research. This marked the ongoing evolution of the CHINARE program in the Antarctic to one with a greater research focus, and with an increased involvement in international scientific collaboration. In this and subsequent issues of Advances in Polar Science, that decade of scientific achievement will be recognized by a number of thematic papers reviewing traverse route between there and the coast. the outcomes from research at Dome A and along the

Recent progress in Chinese polar upper-atmospheric physics research: review of research advances supported by the Chinese Arctic and Antarctic expeditions

It has been more than 30 years since the first Chinese Antarctic Expedition took place. Polar upper atmospheric observations started at this time. First began at Great Wall Station and then at Zhongshan Station in Antarctica, and later in the Arctic at Yellow River Station, Kjell Henriksen Observatory on Svalbard, and at the China-Iceland Joint Aurora Observatory in Iceland. In this paper, we reviewed the advances in polar upper atmosphere physics （UAP） based on the Chinese national Arctic and Antarctic research over the last five years. These included newly deployed observatories and research instruments in the Arctic and Antarctic; and new research findings, from grotmd-based observations, about polar ionosphere dynamics, aurora and particle precipitation, polar plasma convection, geomagnetic pulsations and space plasma waves, space weather in the polar regions, simulations of the polar ionosphere-magnetosphere. In conclusion, suggestions were made for future polar upper atmosphere physics research in China.

Statistical characteristics of ionospheric backscatter observed by SuperDARN Zhongshan radar in Antarctica

Zhongshan HF radar, as one component of SuperDARN, has been established and in operation since April, 2010. Using data from the first two years of its operation, this paper investigates the radar＇s performance, the diurnal and seasonal variations o1 ionospheric echoes, and their dependence on geomagnetic activity. Statistical studies show that the occurrence of echoes in different beams varies at different frequencies, which arises from the direction of the beam and the area over which the beam can achieve the orthogonality condition between the wave vector and the Earth＇s magnetic field. The diurnal variation is obvious with double peak structures both in the occurrence rate and average power at 04-08 UT and 16-17 UT. The line-of-sight velocities are mainly positive on the dayside and negative on the nightside for Beam 0, which is the opposite of the trend for Beam 15. The spec- tral widths on the dayside are often higher than those on the nightside owing to the high energy particle precipitation in the cusp region. The seasonal variations are more obvious for those beams with larger numbers. The occurrence, the average power, the line-of-sight velocity, and the spectral widths are generally larger in the winter months than in the summer months. The influence of geomagnetic activity on radar echoes is significant. The peak echo occurrence appears on the dayside during geomagnetically quiet times, and shifts toward the nightside and exhibits an obvious decrease with increasing Kp. With increasing geomagnetic activity, the line-of-sight velocities increase, whereas the spectral widths decrease. The frequency dependence is investigated and it is found that in the operating frequency bands in 2010, 9-10 MHz is the most appropriate band for the SuperDARN Zhongshan radar.

From mandatory icebreaker guiding to a permission regime: changes to the new Russian legislation of the Northern Sea Route

This article focuses on two issues. The first concerns definitions of the Northern Sea Route （NSR） in old and new Russian legislation, and the second relates to Russian rules on icebreaker guiding. Based on a comprehensive comparative analysis of relevant Russian legal provisions enacted in 2013 and previous laws in this area, we offer the following conclusions. （1） Our legal analysis indicates that Russia＇s view of the NSR as a historical national transportation route has not changed. However, the new law redefines the scope and coverage of the NSR, which now comprises the internal waters, territorial sea, adjacent zone, and the exclusive economic zone of the Russian Federation. In fact, the new law resolves previous ambiguity regarding extension of the NSR boundary to the high seas. （2） Based on an analysis of the new rules on icebreaker guiding, the article concludes that NSR is transitioning from a mandatory icebreaker guiding regime into a permit regime. This is particularly evident in its provision of a concrete, practical, and predictable clause on permissible or impermissible conditions relating to independent navigation. According to the new rules, it is possible for foreign ships to undertake independent navigation in the NSR. The Russian NSR policy, therefore, appears to have changed significantly, and has future potential for opening the NSR up to the international community.

Progress in polar upper atmospheric physics research in China

The Chinese Antarctic Great Wall, Zhongshan, Kunlun and Arctic Yellow River stations have unique geographical locations, well suited to carry out polar upper atmospheric observations. This paper reviews the tremendous history of nearly 30 years of Chinese polar expeditions and major progress in polar upper atmospheric physics research. This includes the polar upper atmospheric physics conjugate observation system at Zhongshan Station in the Antarctic and Yellow River Station in the Arctic, and original research achievements in polar ionospheric fields, aurora and particle precipitation, the polar current system, polar plasma convection, geomagnetic pulsations and space plasma waves, inter-hemispheric comparisons of the space environment, space weather in polar regions, power spectrum of the incoherent scatter radar, ionospheric heating experiments and polar meso- spheric summer echoes, polar ionosphere-magnetosphere numerical simulation and others. Finally, prospects for Chinese polar upper atmospheric physics research are outlined.

Chinese Antarctic Magnetometer Chain at the Cusp Latitude

A Chinese Antarctic Magnetometer （CAM） chain from Zhongshan Station （ZHS） to Dome-A （DMA） has been established since February 2009. A regular magnetometer is operated at ZHS, and four low power magnetometers are operated along the interior route from ZHS to DMA in the cusp latitude, extending over a distance of 1260 km. These stations fill an important void in the Antarctic magnetometer network. Furthermore, the CAM chain is magnetically conjugated with the Arctic region reaching from the Svalbard archipelago to Daneborg, on the east coast of Greenland. Conjugate measurements using the Arctic and Antarctic magnetometers provide excellent opportunities to investigate phenomena related to the coupling of the solar wind to the magnetosphere and ionosphere, such as magnetic impulse events, flux transfer events, traveling convection vortices and ultra-low frequency waves.

Simultaneous optical and radar observations of poleward moving auroral forms under different IMF conditions

Using high temporal resolution optical data obtained from three-wavelength all-sky imagers at Chinese Yellow River Station in the Arctic, together with the EISCAT Svalbard radar （ESR） and SuperDARN radars, we investigated the dayside pole- ward moving auroral forms （PMAFs） and the associated plasma features in the polar ionosphere under difibrent interplanetary magnetic field （1MF） conditions, between 0900 and 1010 UT on 22 December 2003. Simultaneous optical and ESR observations revealed that all PMAFs were clearly associated with pulsed particle precipitations. During northward IMF, particles can precipi- tate into lower altitudes and reach the ionospheric E-region, and there is a reverse convection cell associated with these PMAFs. This cell is one of the typical signatures of the dayside high-latitude （lobe） reconnection in the polar ionosphere. These results indicate that the PMAFs were associated with the high-latitude reconnection. During southward IMF, the PMAFs show larger lati- tudinal motion, indicating a longer mean lifetime, and the associated ionospheric features indicate that the PMAFs were generated by the dayside low-latitude reconnection.

Interplanetary shock-associated aurora

Interplanetary shocks or solar wind pressure pulses have prompted impacts on Earth's magnetospheric and ionospheric environment, especially in causing dynamic changes to the bright aurora in the polar ionosphere. The auroral phenomenon associated with shock impingements, referred to as shock aurora, exhibits distinct signatures differing from other geophysical features on the dayside polar ionosphere. Shock aurora provides a direct manifestation of the solar wind–magnetosphere–ionosphere interaction. Imagers onboard satellites can obtain the associated large-scale auroral characteristics during shock impingement on the magnetopause. Therefore, auroral data from satellites are very useful for surveying the comprehensive features of shock aurora and their general evolution. Nonetheless, the ground-based high temporal-spatial resolution all-sky imagers installed at scientific stations play an essential role in revealing medium-and small-scale characteristics of shock aurora. Here, we focus on shock aurora imaging signatures measured by imagers onboard satellites and ground-based all-sky imagers.

Editorial

This issue of Advances in Polar Science exclusively contains papers that are about polar research programs and activities of countries in the Asian region. Although several Asian nations (Japan, India, China, Republic of Korea) have been involved in Antarctic research for more than 30 years, there is a new and growing interest in the Asian region in scientific activity in both the Arctic and Antarctic.

Identification of optical auroras caused by mantle precipitation with the aid of particle observations from DMSP satellites

Particle observations of the Defense Meteorological Satellite Program(DMSP) show that discrete auroral structures commonly exist in the region of the plasma mantle, but the optical features of the aurora generated by particles from the plasma mantle(called ‘mantle aurora’ in this paper) have not been established. A comparison of 7-year optical auroral observations made at the Yellow River Station with conjugate particle observations obtained from the DMSP confirm that mantle auroras have common features and can be clearly identified from all-sky imager observations. The mantle auroras normally present as sporadic and weak auroral structures split poleward of the dayside auroral oval. They are observed in both the green and red lines with the intensity of the red line being greater than that of the green line. In this paper, we illustrate typical mantle auroras and provide statistics on 55 mantle aurora cases that are confirmed by particle observation by the DMSP. Statistical results show that the occurrence of the mantle aurora has no clear dependence on the IMF By and Bz conditions, but the motion of the mantle aurora strongly depends on the IMF By, which indicates that the generation of the mantle aurora is intimately related to the dayside magnetopause reconnection. With the fundamental criteria for distinguishing the mantle aurora presented in this paper, we will be able to independently identify the mantle auroras from ground optical observations. This will allow us to investigate the physical processes that occur in the plasma mantle by monitoring the evolution of the auroral forms.

SuperDARN CUTLASS Finland radar observations of high-latitude magnetic reconnections under northward interplanetary magnetic field (IMF) conditions

A number of backscatter power enhancement events with "equatorward-moving radar auroral forms" in the high-latitude ionosphere were observed by SuperDARN CUTLASS Finland radar when the IMF was northward during 09:00 -10:00 UT on 26 March 2004. These events were also associated with sunward flow enhancements at each location in the Northern Hemisphere which were shown in ionospheric convections measured by the SuperDARN radars. These are typical features of high-latitude (lobe) magnetic reconnections. The durations of the velocity enhancements imply that the evolution time of the lobe reconnections is about 8-16 min from their origin at the reconnection site to their addition to the magnetotail lobe again. In additional, the Double Star TC-1 spacecraft was moving from magnetosheath into magnetosphere, and crossing the magnetopause near the subsolar region during this interval, and observed typical low-latitude magnetic reconnection signatures. This infers that the dayside high- and low-latitude reconnections may occur simultaneously.

Dayside poleward moving auroral forms and ionospheric convection under stable interplanetary magnetic field (IMF) conditions

Using high temporal resolution optical data obtained from three-wavelength all-sky imagers over six winters continuously at Yellow River Station (78.92°N,11.93°E) in Arctic,we statistically investigated the dependence of location of poleward moving auroral forms (PMAFs) on the interplanetary magnetic field (IMF) B z and B y components as a function of MLT and MLAT under stable IMF conditions.It is found that more PMAFs occurred in lower latitude for Bz<0 and there was less evident IMF B y-related prenoon-postnoon asymmetry for Bz<0 than for Bz>0.We found that the PMAFs were distributed over a wide range of MLT when Bz<0,which indicates that the reconnection X-line might spread like an 'S' shape.However,during northward IMF,PMAFs were observed predominantly prenoon for IMF By>0 and postnoon for IMF By<0 associating with the effect of the high-latitude reconnection,which is largely consistent with the theoretical model of the convection flow.