Editing Electromagnet (section)

=== Bitter electromagnets ===
{{main|Bitter electromagnet}}
Both iron-core and superconducting electromagnets have limits to the field they can produce. Therefore, the most powerful man-made magnetic fields have been generated by ''air-core'' non-superconducting electromagnets of a design invented by [[Francis Bitter]] in 1933, called Bitter electromagnets.<ref name="MagnetLabU">{{cite web
 |last        = Coyne
 |first       = Kristin
 |title       = Magnets: from Mini to Mighty
 |website     = Magnet Lab U
 |publisher   = National High Magnetic Field Laboratory
 |year        = 2008
 |url         = http://www.magnet.fsu.edu/education/tutorials/magnetacademy/magnets/fullarticle.html
 |access-date = 2008-08-31
 |url-status  = dead
 |archive-url = https://web.archive.org/web/20080917101425/http://www.magnet.fsu.edu/education/tutorials/magnetacademy/magnets/fullarticle.html
 |archive-date = 2008-09-17
}}</ref> Instead of wire windings, a Bitter magnet consists of a [[solenoid]] made of a stack of conducting disks, arranged so that the current moves in a helical path through them, with a hole through the center where the maximum field is created. This design has the mechanical strength to withstand the extreme [[Lorentz force]]s of the field, which increase with ''<math>B^2</math>''. The disks are pierced with holes through which cooling water passes to carry away the heat caused by the high current. The strongest continuous field achieved solely with a resistive magnet is 41.5&nbsp;T {{as of|2017|August|22|lc=y}}, produced by a Bitter electromagnet at the [[National High Magnetic Field Laboratory]] in [[Tallahassee]], [[Florida]].<ref name="NHMFL record">{{cite news |title=MagLab Reclaims Record for Strongest Resistive Magnet |url=https://nationalmaglab.org/news-events/news/strongest-resistive-magnet |access-date=14 May 2023 |publisher=National High Magnetic Field Laboratory |date=22 August 2017}}</ref><ref name="NHMFL Design and Testing 41.5T"> {{cite journal |last=Toth | first=J. | author2=Bole, S.T. |title="Design, Construction, and First Testing of a 41.5 T All-Resistive Magnet at the NHMFL in Tallahassee,"|journal=IEEE Transactions on Applied Superconductivity | volume=28 | issue=3|pages=1–4 |doi=10.1109/TASC.2017.2775578| publisher=IEEE | date=April 2018| s2cid=7923594 | doi-access=free | bibcode=2018ITAS...2875578T }} </ref> The previous record was 37.5&nbsp;T.<ref name="Dutch record">{{cite news |title=HFML sets world record with a new 37.5 tesla magnet |url=http://www.ru.nl/hfml/news/news/news-items/hfml-sets-world/ |access-date=21 May 2014 |publisher=High Field Magnet Laboratory |date=31 March 2014 |url-status=dead |archive-url=https://web.archive.org/web/20150904093407/http://www.ru.nl/hfml/news/news/news-items/hfml-sets-world/ |archive-date=4 September 2015 }}</ref> The strongest continuous magnetic field overall, 45&nbsp;T,<ref name="MagnetLabU" /> was achieved in June 2000 with a hybrid device consisting of a Bitter magnet inside a superconducting magnet.

The factor that limits the strength of electromagnets is the inability to dissipate the enormous waste heat, so more powerful fields, up to 100&nbsp;T,<ref name="MagnetLab" /> have been obtained from resistive magnets by sending brief pulses of high current through them; the inactive period after each pulse allows the heat produced during the pulse to be removed before the next pulse. 
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