Polarized lightning arrestors

1. An active lightning protection system for a site, the system comprising:

a sensor arrangement arranged to detect one or more of a lightning step leader descending from an atmospheric charge accumulation and/or an upward earth streamer ascending toward the atmospheric charge accumulation;

risk-assessment circuitry coupled to the sensor arrangement and configured to provide a risk assessment of a lightning strike;

one or more reconfigurable lightning protection elements responsive to the risk assessment of a lightning strike, wherein the lightning protection elements comprise a plurality of lightning arrestors and one or more voltage biasing elements coupled to the plurality of lightning arrestors; and

control circuitry configured to bias a first of the lightning arrestors to a different respective potential than a second of the lightning arrestors to control a location of a conducting path from the atmospheric charge accumulation to ground in response to the risk assessment of a lightning strike.

2. The system of claim 1 , wherein the sensor arrangement is configured to detect a strength, a location, a direction and/or timing of the lightning step leader, the upward earth streamer, and/or the atmospheric charge accumulation.

3. The system of claim 2 , wherein the lightning protection elements comprise one or more adjustable-height lightning arrestors whose heights are adjusted by the control circuitry in response to the risk assessment of a lightning strike.

4. The system of claim 1 , wherein a difference in the respective potentials of the first and the second of the lightning arrestors is adjustable in response to the risk assessment of a lightning strike.

5. The system of claim 1 , wherein the one or more voltage biasing elements are arranged to bias the first of the lightning arrestors to a non-zero potential relative to a local ground potential.

6. The system of claim 1 , wherein the one or more voltage biasing elements are arranged to bias the plurality of lightning arrestors to establish a potential gradient across the plurality of lightning arrestors.

7. The system of claim 1 , wherein the one or more voltage biasing elements comprise an EMF source.

8. The system of claim 1 , wherein the one or more voltage biasing elements comprise a capacitor and/or a voltage amplifier.

9. The system of claim 1 , wherein the one or more voltage biasing elements comprise a photovoltaic array.

10. The system of claim 1 , wherein at least one of the plurality of lightning arrestors has a rod-, a rope-, a cable-, a wire-, a netting-, a strip-, a plate-, a panel-, a wall-, and/or an extended surface-shape.

11. The system of claim 1 , wherein at least one of the plurality of lightning arrestors is arranged to emit charges substantially non-directionally.

12. The system of claim 1 , wherein at least one of the plurality of lightning arrestors is arranged to emit charges substantially directionally.

13. The system of claim 1 , wherein the first of the lightning arrestors and the second of the lightning arrestors are spaced less than a critical distance apart so that zones of protection of the first and second lightning arrestors overlap.

14. The system of claim 1 , wherein the first of the lightning arrestors is biased to a positive potential, and the second of the lightning arrestors is biased to a negative potential.

15. The system of claim 1 , disposed at a site, wherein the first of the lightning arrestors is biased to a positive potential relative to a site potential, and the second of the lightning arrestors is biased to a negative potential relative to the site potential.

16. The system of claim 1 , wherein the plurality of lightning arrestors comprises a sequence of positively and negatively biased lightning arrestors.

17. The system of claim 1 , wherein the plurality of lightning arrestors comprises a sequence of lightning arrestors that are positively and negatively biased with respect to a site potential.

18. The system of claim 1 , wherein the sensor arrangement comprises at least one sensor arranged to sense a weather condition, a site potential value, and/or a geopotential value.

19. The system of claim 1 , wherein the lightning protection elements include a device coupled to the sensor arrangement and arranged to prepare a charge conductive path through the atmosphere in response to the detected step leader and/or the detected upward earth streamer.

20. The system of claim 19 , wherein the charge conductive path comprises excited molecules and/or ionized molecules.

21. The system of claim 19 , wherein the device is arranged to prepare a charge conductive path whose position and/or direction is responsive to a location and/or direction of the detected step leader and/or the detected upward earth streamer.

22. The system of claim 19 , wherein the device is arranged to prepare a charge conductive path whose position and/or direction is responsive a location the atmospheric charge accumulation.

23. The system of claim 19 , wherein the device is arranged to create a charge conductive path which allows charges in the atmospheric charge accumulation to dissipate.

24. The system of claim 19 , wherein the device is arranged to prepare a charge conductive path through the atmosphere to ground in response to a detected step leader and/or upward earth streamer.

25. The system of claim 19 , wherein the system is deployed to protect a site, and wherein a ground termination point of the charge conductive path is sufficiently remote to avoid a direct lightning strike at the site.

26. The system of claim 19 , wherein the sensor network is further configured to detect a start of a main or return lightning stroke.

27. The system of claim 19 , wherein the device is arranged to create the charge conductive path in response to a detected start of a main or return lightning stroke.

28. The system of claim 19 , wherein the device arranged to create a charge conductive path through the atmosphere comprises a laser.

29. The system of claim 28 , wherein the laser is arranged to emit a light beam through the atmosphere.

30. The system of claim 19 , wherein the device comprises a charge-emitting device configured to inject charges in the atmosphere.

31. The system of claim 30 , wherein the charge-emitting device is configured to emit charges substantially directionally.

32. The system of claim 19 , wherein the device comprises a charge-emitting device configured to inject charges in the ground.

33. The system of claim 32 , wherein the device is arranged to inject charges at about a ground termination location of the charge conductive path.

34. The system of claim 19 , wherein the device arranged to create a charge conductive path through the atmosphere comprises a capacitor.

35. The system of claim 19 , wherein a ready-to-operate status of the device is configured to responsive to the risk assessment of a lightning strike.

36. The system of claim 1 , wherein the at least one lightning protection elements include a device coupled to the sensor arrangement and arranged to alter a ground potential in response to a detected step leader and/or upward earth streamer.

37. The system of claim 36 , wherein the system is deployed to protect a site, and wherein the device is arranged to alter a ground potential to direct a lightning strike away from the site.

38. The system of claim 36 , wherein the device comprises a charge-emitting device configured to inject charges in the ground.

39. The system of claim 36 , wherein the device is arranged to inject charges at about a selected ground termination location for a lightning strike.

40. The system of claim 36 , wherein the device arranged to alter a ground potential comprises a capacitor.

41. The system of claim 40 , wherein the device comprises a circuit configured to fire a capacitor

42. The system of claim 36 , wherein the device arranged to alter a ground potential comprises a current source.