The first super geomagnetic storm of solar cycle 24: “The St. Patrick’s day event (17 March 2015)”

Earth, Planets and Space

Table 2 Related information for the CME15, Shock and ICME17 during 15–17 March 2015

	Start time^a	r ^b	Ending time^c	Δr ^d	Δt ^e (h)	V ^f_shock/CME (km/s)	V′^g (km/s)	Δt ^h_pred (h)	Δt ⁱ_ERR (h) ( %)
	UT (Mar. 15)	Rs	UT (Mar. 17)	Rs	Δt ^e (h)	V ^f_shock/CME (km/s)	V′^g (km/s)	Δt ^h_pred (h)	Δt ⁱ_ERR (h) ( %)
Shock_C3	2:30	6.95–18.82	03:57	204.05	49.45	796.6	668	58.97	16
ICME_C3	2:30	6.95–18.82	10:38	204.05	56.13^j	701.8	668	58.96 ^k	5 ^l
Shock_C2	2:00	4.15–6.61	03:57	206.85	49.95	799.5	606	65.00	30
ICME_C2	2:00	4.15–6.61	10:38	206.85	56.63	705.0	606	65.00	15

^aCME/shock was observed by SOHO/LASCO
^bLocation of leading edge of CME measured by C3 or C2 (units in Rs)
^cStarting point at 1 AU (Wind)
^dDistance between the initial point observed by C3 and Wind (units in Rs), and 1 Rs = 6.95 × 10⁵ km
^eΔt: traveling time of shock/CME between 6.95 Rs and 1 AU (units in hours), and 1 AU equals to 215 Rs
^f V _shock/CME = Δr/Δt (units in km/s)
^g V′: V _CME/shock measured near the Sun between 6.95 and 18.82 Rs (units in km/s)
^hΔt _prediction: predicted traveling time for shock/CME propagating from 6.95 Rs to Wind (units in hours)
ⁱΔt _ERR: error on the Δt _pred = (Δt _pred − Δt)/Δt × 100 (%)
^jTraveling time of ICME17 from 6.95 Rs to Wind spacecraft, ICME was seen by C3 at 2:30 UT on 15 March and recorded by Wind at 10:38 UT on 17 March [Δt = 2 × 24 + (10–2) + (38–30)/60 = 56.13 h]. Wind orbited at 258.7 R _E (GSE). Earth was at 213.938 Rs. Wind was at ~211 Rs (GSE). Therefore V _CME = Δr/Δt = (204.05 Rs/56.13 h) = 701.8 km/s
^k204.05 × 6.95 × 10⁵/(668 × 3600) = 58.96 h
^l(58.96−56.13)/56.13 ≡ 5 %