Role of high-speed solar wind streams on cosmic ray nucleonic intensity and solar/interplanetary/geomagnetic parameters during low amplitude days

There are two types of high-speed solar wind streams classified in two categories: coronal hole associated and flare generated streams. These two types of streams are classified in two categories based on magnetic field and solar wind plasma parameters. In the present work we have studied the characteristic of cosmic ray nucleonic intensity along with solar/geomagnetic parameters and their inter correlation on the onset of highspeed solar wind streams during low amplitude days. The two types of solar wind streams (corotating streams and flare-generated streams) produced significant deviations in cosmic ray intensity and other solar/ geomagnetic parameters during low amplitude anisotropic wave train events. The cosmic ray intensity tends to decrease, whereas the solar wind velocity tends to increase after the on set of corotating stream. Both the geomagnetic activity index (Ap) and disturbance storm time index (Dst) decreases sharply from one day prior to one day after the arrival of corotating stream. Both of these are also found to depressed significantly five days after the arrival of corotating stream. Both the cosmic ray intensity as well solar wind velocity are found to decrease prior to the arrival of flare generated stream and increase after the arrival of stream with a time lag of 1 or 2 days. The solar activity (represented by sunspot numbers) increases sharply prior to the arrival of flare-generated stream up to day +3 with a significant depression on the onset of stream. It is noteworthy that both Ap and Dst index significantly depressed on the arrival of flare-generated stream, whereas both of these are found to increase prior to the arrival of stream. PACS: 96.40.Kk, 96.40. -z, 96.40.cd