Two populations of twisted magnetic field tubes , or flux ropes ( hereafter , FRs ) , are detected by in situ measurements in the solar wind .
While small FRs are crossed by the observing spacecraft within few hours , with a radius typically less than 0.1AU , larger FRs , or magnetic clouds ( hereafter , MCs ) , have durations of about half a day .
The main aim of this study is to compare the properties of both populations of FRs observed by the Wind spacecraft at 1 AU .
To do so , we use standard correlation techniques for the FR parameters , as well as histograms and more refined statistical methods .
Although several properties seem at first different for small FRs and MCs , we show that they are actually governed by the same propagation physics .
For example , we observe no in situ signatures of expansion for small FRs , contrary to MCs .
We demonstrate that this result is in fact expected : small FRs expand similarly to MCs , as a consequence of a total pressure balance with the surrounding medium , but the expansion signature is well hidden by velocity fluctuations .
Next , we find that the FR radius , velocity and magnetic field strength are all positively correlated , with correlation factors than can reach a value > 0.5 .
This result indicates a remnant trace of the FR ejection process from the corona .
We also find a larger FR radius at the apex than at the legs ( up to three times larger at the apex ) , for FR observed at 1 AU .
Finally , assuming that the detected FRs have a large-scale configuration in the heliosphere , we derived the mean axis shape from the probability distribution of the axis orientation .
We therefore interpret the small FR and MC properties in a common framework of FRs interacting with the solar wind , and we disentangle the physics present behind their common and different features .