Richard Zen:
what you had there was an impermanent concentration state.
Thank you for your answer and for the suggestion.
Is it a "generic" concentration state? Can I use it to enter jhana?
I haven't been able to enter any jhana consistently, although I recognize the general features of the strata (as KF puts it). In Daniel's numbering I usually play around 11.4.5, 11.4.6 and 11.4.7, trying learn to distinguish them.
Can I use that state to improve my practice in any way?
Thanks again.