CME shock Arrival Time
CME shock Arrival Time
In a previous work (Paouris and Mavromichalaki in Solar Phys. 292, 30, 2017) ,
we presented a total of 266 interplanetary coronal mass ejections (ICMEs) with as much
information as possible.We developed a new empirical model for estimating the acceleration
of these events in the interplanetary medium from this analysis. In this work, we present a
new approach on the effective acceleration model (EAM) for predicting the arrival time of
the shock that preceds a CME, using data of a total of 214 ICMEs. For the first time, the
projection effects of the linear speed of CMEs are taken into account in this empirical model,
which significantly improves the prediction of the arrival time of the shock. In particular, the
mean value of the time difference between the observed time of the shock and the predicted
time was equal to +3.03 hours with a mean absolute error (MAE) of 18.58 hours and a root
mean squared error (RMSE) of 22.47 hours. After the improvement of this model, the mean
value of the time difference is decreased to −0.28 hours with an MAE of 17.65 hours and
an RMSE of 21.55 hours. This improved version was applied to a set of three recent Earthdirected
CMEs reported in May, June, and July of 2017, and we compare our results with
the values predicted by other related models.
According to this work (Paouris and Mavromichalaki in Solar Phys. 292, 30, 2017) , the effective acceleration of a CME shows a very good
correlation with the linear speed which calculated by LASCO/SOHO coronagraph data, with a very high correlation coefficient of r = 0.98.
According this model it is possible to calculate the effective acceleration (α) of a CME using only the initial speed of the CME (u) through the second order equation:
α = 1.45 [m/s 2] – 27.40 × 10-4 [10-3 s-1] u – 1.28 × 10-6 [10-6 m-1] u2,
where α is in m/s2 and u in km/s.
This new service, based on this model is able to calculate the CME’s shock arrival time using as inputs: a) the distance of Earth using high accuracy based on a code which takes into account the epoch and aphelion/perihelion of the Earth, b) the initial speed of CME (u) from almost real time data (such as CACTUS) and c) the effective acceleration calculated by the model which mentioned before. This result will be given as an output txt with:
a) the acceleration/deceleration of the shock,
b) the estimated velocity of the shock at the distance of 1 AU and
c) the arrival time of the shock of the CME.
This new service, based on this model is able to calculate the CME’s shock arrival time using as inputs: a) the distance of Earth using high accuracy based on a code which takes into account the epoch and aphelion/perihelion of the Earth, b) the initial speed of CME (u) from almost real time data (such as CACTUS) and c) the effective acceleration calculated by the model which mentioned before. This result will be given as an output txt with:
a) the acceleration/deceleration of the shock,
b) the estimated velocity of the shock at the distance of 1 AU and
c) the arrival time of the shock of the CME.