Automatic Detection Algorithm of the Solar Wind Dynamic Pressure Pulses with the Application to WIND High-resolution Data

Abstract:

Solar wind dynamic pressure pulses (DPPs), i.e. the abrupt change in solar wind dynamic pressure, can affect the energy and momentum transfer from the solar wind to the magnetosphere-ionosphere coupling system, and as a result, cause various types of disturbances. To detect the DPPs rapidly from the solar wind plasma data, an automated DPP-hunting computer code is developed. In order to meet the research requirements, it demands not only identify and isolate the special structure, but also automatically select appropriate preceding and succeeding reference data points, for which there are very small variations in solar wind dynamic pressure, to represent the plasma status before and after the pressure change, as well as determine the DPP fine ramp structure where the solar wind transits from one relatively quiet status to another. It indicates from the high-resolution measurements that the pressure changes can occur on time scale from a few seconds to many minutes. The code can be used to hunt DPPs of arbitrary ramp length and arbitrary pressure change amplitude by adjusting the criteria. It can be applied to variable data rates. The strong DPPs that have very large pressure change are most geoeffective so as to affect the near-Earth environment intensively. Thus the code also benefits the space weather warning or forecasting when applied to the real-time spacecraft data to hunt the large DPPs. Here we present the major algorithm to identify and define the upstream, downstream and the ramp region. The effectiveness of this code is tested on WIND high-resolution measurements covering the 23th solar cycle. We will show the test results during the interval of magnetic cloud (MC) and corotating interation region (CIR). The statistical results of DPPs in 23th solar cycle are also discussed.