<html><head></head><body><div><strong>From:
</strong>
"Flexman, Connor" <connor_flexman@brown.edu>
<br><blockquote class="mori" style="margin:0 0 0 .8ex;border-left:2px blue solid;padding-left:1ex;"><div class="body"> <div><div class="mcntgmail_extra"><div class="mcntgmail_quote"><br></div></div><div class="mcntgmail_extra"><div>Unfortunately, the biggest issue seems to be extending the field far from the spacecraft. As you noted, the field falls off as inverse square of the distance, so unfortunately the field 1 cm from the center of the neodymium magnet is reduced by 4 orders of magnitude a meter out. </div></div></div></div></blockquote></div><div><br></div><div><br></div><div>Worse. Magnetic fields are dipoles, so they fall of with the *cube* of distance.</div><div><br></div><div>All references I have seen to protection using magnetic fields have sketched rather extended antennas, solenoids or plasma clouds in order to have more time to deflect and less need for a super-strong field. </div><div><br><br>Anders Sandberg, Future of Humanity Institute Philosophy Faculty of Oxford University</div></body></html>