Accessor for (ACE MAG L2 4-min magnetic field data)
Acknowledgment: CDAS services from NASA/Goddard Space Physics Data Facility (R. McGuire). Time span: Valid formats are YYYY-MM-dd,HH:mm and YYYY-DDD,HH:mm. (Times are optional.) If the end date is omitted, it will default to one day after the start date. Begin date: 1997-09-01,   End date: 2009-06-20. from:     to:
Parameter name	Parameter description
Magnitude	B-field magnitude
BGSEc	Magnetic Field Vector in GSE Cartesian coordinates (4 min)
BGSM	Magnetic field vector in GSM coordinates (4 min)
SC_pos_GSE	ACE s/c position, 3 comp. in GSE coord.
SC_pos_GSM	ACE s/c position, 3 comp. in GSM coord.
Processing may take a few minutes.