Comments on Some Long‐Standing Problems in Storm/Substorm Studies

We identify seven long-standing problems in storm/substorm studies and present our views on them mainly on the basis of earlier literatures, demonstrating that earlier studies should be combined with new results to overcome the difficulties associated with long-standing problems. We introduce a new index AF to monitor the upward field-aligned currents (FAC) and show that it is far better correlated to the Dst index than the AE index.