A Statistical Study on DH CMEs and Its Geoeffectiveness

Table 1

Properties of type-II bursts, flares, and CMEs in geoeffective and nongeoeffective events.

S. no.	Properties	Non-geoeffective events	Geoeffective events	𝑡-test 𝑃 value (%)
	DH-type-II burst
1	Starting frequency (MHz)	10.14	10.99	21.32
2	Ending frequency (MHz)	2.38	1.52	7.09
3	Band width (MHz)	7.76	9.46	2.45
4	Duration (min)	288	958	0.007
	Flares
5	Flare duration (min)	50	70	6.3
6	Flare rise time (min)	25.97	35.18	6.9
7	Flare decay time (min)	24.66	35.12	10.55
	CMEs
8	CME speed (km s^−1)	1170	1263	35.39
9	Width (deg)	247	337	≪1
10	Acceleration (m s^−2)	−4.25	−19.23	5.05