Geoeffectiveness of CMEs - STP science case

Aim

Link solar, interplanetary and geomagnetic data into a workflow that investigates which Coronal Mass Ejections (CME) produce geomagnetic storms at the Earth, and how the solar wind magnetic field and plasma parameters influence this process.

Datasets required

• Geomagnetic indeces from UKSSDC at RAL.
• Interplanetary magnetic field and plasma data from the ACE spacecraft.

Summary

The workflow steps are described at STPSolarEventCoincidenceSteps, and are summarised in the following workflow diagram. Below are comments related to steps in the workflow. We test the various steps of the workflow on an example time period, March 2002.

1. Get CME list

A query is sent to the LASCO CME catalogue via EGSO SEC to retrieve a list of candidate CMEs. Some selection criterion on the type of CME needs to be specified. Initially, we select only halo CMEs by sending the following query:

SELECT * FROM lasco_cme_cat WHERE time_start>='2002-03-01 00:00:00' AND time_start <= '2002-03-31 23:59:59' AND pa_width = 360

We get back the following votable:

2. Build time window for geoeffectiveness search.

The measured plane of the sky speed of the CME given in the votable above (e.g. linear_speed, linear fit to coronograph images), can be used to estimate the travel time to the Earth and build a time window in which to search for signs of CME arrival near Earth and geomagnetic effects. This is done within a workflow script.

-- SilviaDalla - 12 Jun 2005

• stpscicase.html: Table output of STP science case