[1] We present THEMIS observations of the near-Earth plasma sheet that permit us to assess the geometrical structure of the magnetotail prior to dipolarization. Latitudinal profiles of the magnetic field were obtained by five spacecraft simultaneously around the magnetic equator at a distance of X GSM ∼ −10 R E in the premidnight for two events. It is found that the strength of normal magnetic field B z was increased with a distance from the magnetic equator, which differs considerably from the standard magnetic field model. Instead, the observation can be explained by a magnetic field model that has a minimum in the equatorial field strength (minimum B), as required from the force-balanced magnetotail model with steady earthward convection. Moreover, the analyses showed that the feature of minimum B sustained continuously for ∼20 min before dipolarization onsets.

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Due to the expeditious expansion of wearable electronics, all-solid-state flexible supercapacitors are being contemplated as promising energy-storage devices. Through the successful preparation of large quantities of high-quality semiconducting-type thin molybdenum disulfide (MoS 2 ) sheets suspended in water, the authors have developed an environmentally friendly and simple method to fabricate ternary flexible electrodes with MoS 2 , polyaniline (PANI), and carbon nanotubes (CNTs). The resulting MoS 2 /PANI/CNT all-solid-state supercapacitor can be easily integrated in series to power commercial light-emitting diodes without an external bias voltage. In addition, such a supercapacitor exhibits remarkable energy density (0.013 Wh cm −3 ) and power density (1.000 W cm −3 ), thus making it superior to commercially available lithium thinfilm batteries (4 V/500 μA h) and 2.75 V/44 mF activated carbon electrochemical capacitors. These results demonstrate that the exfoliated MoS 2 -based composite is a promising material for the development of high-performance and low-cost energystorage devices.

A statistical study of the structure of Earth's magnetopause is carried out by analyzing two‐year AMPTE/IRM plasma and magnetic field data. The analyses are based on the minimum variance analysis (MVA), the deHoffmann‐Teller (HT) frame analysis and the Walén relation. A total of 328 magnetopause crossings are identified and error estimates associated with MVA and HT frame analyses are performed for each case. In 142 out of 328 events both MVA and HT frame analyses yield high quality results which are classified as either tangential‐discontinuity (TD) or rotational‐discontinuity (RD) structures based only on the Walén relation: Events withSWA ≤ 0.4 (SWA ≥ 0.5) are classified as TD (RD), and rest (with 0.4 < SWA < 0.5) is classified as “uncertain,” where SWA refers to the Walén slope. With this criterion, 84% of 142 events are TDs, 12% are RDs, and 4% are uncertain events. There are a large portion of TD events which exhibit a finite normal magnetic field component Bnbut have insignificant flow as compared to the Alfvén velocity in the HT frame. Two‐dimensional Grad‐Shafranov reconstruction of forty selected TD and RD events show that single or multiple X‐line accompanied with magnetic islands are common feature of magnetopause current. A survey plot of the HT velocity associated with TD structures projected onto the magnetopause shows that the flow is diverted at the subsolar point and accelerated toward the dawn and dusk flanks.

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