Small‐scale magnetic flux ropes in the solar wind

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Abstract
Small‐scale magnetic flux ropes have been discovered in the solar wind at 1 AU in observations from the IMP 8 and WIND spacecraft. These small magnetic structures (diameter of 270 RE, on average) have some similar properties to magnetic clouds (diameters of 0.2–0.3 AU or about 6000–8000 RE), which are well known large‐scale magnetic flux ropes, but have durations of 10s of minutes as opposed to many hours or days for most magnetic clouds. The presence of these small helical field structures suggests that solar wind flux ropes may have a wide‐range of scale sizes, or possibly have a bimodal size distribution, and are perhaps more common than previously estimated. Similarities and differences with magnetic clouds will be discussed. We suggest that these small scale magnetic flux ropes are signatures of magnetic reconnection in the solar wind as opposed to in the solar corona.