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Doubt regarding direction of current during lightning

  1. Sep 29, 2012 #1
    In which direction do current flow during lightning? If it is from cloud to earth, which charge gets accumulated in below part of the cloud?
     
    Last edited: Sep 29, 2012
  2. jcsd
  3. Sep 29, 2012 #2
  4. Sep 29, 2012 #3

    davenn

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    some interesting descriptions in that Wiki link but it could do with some expanding by some one :)

    Having done storm chasing and photography for some 12 years I have seen and photo'ed some of the interesting variations.

    Yes ... as the most common is cloud to cloud strokes some buried in the clouds some visible along the base of the cloud .... the most spectactular being the "Anvil Crawlers" that spread out in all directions.

    Have caught this style on camera a number of times, mainly when the strike has been relatively close within 1 km (1000m)

    Only seen photos, havent observed myself as yet

    Staccato is always spectactular, making a great photo. I have watched complete storms and not seen a staccato strike, yet in another storm they have been common

    Not sure what to make of their comments on this one .... I really dont like that artificially initiated as it gives the impression that its man made. I have only captured 1 Ground to Cloud strike and it was NOT from any sort of tall man made structure. Tho many pix and videos I have see, that has been the case. The often are also inverted Staccato rather than a single channel stroke

    Dave
     
    Last edited: Sep 29, 2012
  5. Sep 29, 2012 #4

    nsaspook

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  6. Oct 1, 2012 #5
    You know current will flow only when the path is complete and closed. In this case, that doesn't happen. Lightning dies after some time? Its not a complete or closed path. How can you tell that charges are flowing or current is flowing?
     
  7. Oct 1, 2012 #6

    davenn

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    why would you say that ? of course the path is completed and massive amounts of current flows in those brief milliseconds :)
    The path is between cloud and cloud or cloud and ground between regions of excessive positive and of excessive negative charges ... the flow of current balances that out

    how can you tell ? you can see and hear the effects of the of the current flowing.
    the brigh glow of the ionised air, the crash of the thunder, the buildings, trees electronics etc that get damaged/destroyed because of the huge current flow

    Dave
     
  8. Oct 1, 2012 #7

    davenn

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    If you looked at any of the links provided by those that responded to you ....
    you would have seen that usually the base of the storm cloud get strongly negatively charged and the ground below it positively charged :smile:

    Dave
     
  9. Oct 1, 2012 #8
    I m asking, where can you see a closed path here? We know, current will flow in a closed path only. It will reach the the ground, but where is the closed path? Also, if there is negative charge below the clouds, negative charge will flow from cloud to ground, which makes current flowing from ground to clouds. What we see is lighting striking from cloud to earth. Will lightning show the direction of current or charge? Also, there are few lightnings in those videos striking from earth towards clouds. What can be the current flow direction in those cases?
     
  10. Oct 1, 2012 #9

    davenn

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    the closed path is the ioniosed air channel between the cloud and the ground

    it is probably difficult to tell in which direction the current flow is as it depends on the type of discharge because we wouldnt know what the polarity of the leader is from the ground see image .....

    attachment.php?attachmentid=51383&stc=1&d=1349075419.gif

    cheers
    dave
     

    Attached Files:

  11. Oct 1, 2012 #10

    davenn

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    The wiki link originally given by Naty1 gives you an answer

    snippet from Wiki.....

    so its tells you that the main discharge is in the return stroke from the positively charged area to the negatively charged area
    which could be either cloud to ground or ground to cloud depending on how the charges are distributed as in the diagrams above

    Dave
     
    Last edited: Oct 1, 2012
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