A particle in hyperbolic motion produces electric fields that appear to terminate in mid-air, violating Gauss's law. The resolution to this paradox has been known for sixty years but exactly why the naive approach fails is not so clear.

1.
The entirexy-plane first “sees” the charge at time t = 0. If this seems surprising, refer to Appendix  A.
2.
The fields of a point charge in hyperbolic motion were first considered by
M.
Born
, “
Die Theorie des starren Elektrons in der Kinematik des Relativitätsprinzips
,”
Ann. Phys.
30
,
1
56
(
1909
).
For the early history of the problem see
W.
Pauli
,
Theory of Relativity
(reprint by
Dover
,
New York
,
1981
), Section 32(γ).
For a comprehensive history see
E.
Eriksen
and
Ø.
Grøn
, “
Electrodynamics of Hyperbolically Accelerated Charges. I. The Electromagnetic Field of a Charged Particle with Hyperbolic Motion
,”
Ann. Phys.
286
,
320
342
(
2000
).
See also
S.
Lyle
,
Uniformly Accelerating Charged Particles: A Threat to the Equivalence Principle
(
Springer
,
Berlin
,
2008
).
3.
See, for example,
D. J.
Griffiths
,
Introduction to Electrodynamics
, 4th ed. (
Pearson
,
Upper Saddle River, NJ
,
2013
), Eq. (10.72.)
4.
This field was first obtained by
G. A.
Schott
,
Electromagnetic Radiation
(
Cambridge U.P.
,
Cambridge, UK
,
1912
), pp.
63
69
.
5.
E. M.
Purcell
and
D. J.
Morin
,
Electricity and Magnetism
, 3rd ed. (
Cambridge U.P.
,
Cambridge, UK
,
2013
), Section 5.6.
6.
J. M.
Aguirregabiria
,
A.
Hernández
, and
M.
Rivas
, “
δ-function converging sequences
,”
Am. J. Phys.
70
,
180
185
(
2002
), Eq. (50).
The fields of a massless point charge are considered also in
J. D.
Jackson
,
Classical Electrodynamics
, 3rd ed. (
Wiley
,
New York
,
1999
),
Prob. 11.18,
W.
Thirring
Classical Mathematical Physics: Dynamical Systems and Field Theories
(
Springer-Verlag
,
New York
,
1997
), pp.
367
368
and
M. V.
Kozyulin
and
Z. K.
Silagadze
, “
Light bending by a Coulomb field and the Aichelburg-Sexl ultraboost
,”
Eur. J. Phys.
32
,
1357
1365
(
2011
), Eq. (20).
7.
H.
Bondi
and
T.
Gold
, “
The field of a uniformly accelerated charge, with special reference to the problem of gravitational acceleration
,”
Proc. R. Soc. London Ser. A
229
,
416
424
(
1955
).
D. G.
Boulware
, “
Radiation from a uniformly accelerated charge
,”
Ann. Phys.
124
,
169
188
(
1980
) obtained Eq. (21) using the truncated hyperbolic model.
The latter was also explored by
W.
Thirring
A Course in Mathematical Physics: Classical Field Theory
, 2nd ed. (
Springer-Verlag
,
New York
,
1992
), p.
78
. See also Lyle, ref. 2, Section 15.9.
8.
Reference 3, Eqs. (10.46) and (10.47).
9.
See Appendix  B for details of these calculations. Equation (29) reduces to Eq. (9), of course, when t = 0 and s = x.
10.
R.
Jackiw
,
D.
Kabat
, and
M.
Ortiz
, “
Electromagnetic fields of a massless particle and the eikonal
,”
Phys. Lett. B
277
,
148
152
(
1992
).
11.
Potentials (30) and (31) satisfy the Lorenz gauge condition, as does Eq. (37), but Eq. (36) does not.
12.
The delta-function terms in the potentials were first obtained by
T.
Fulton
and
F.
Rohrlich
, “
Classical radiation from a uniformly accelerated charge
,”
Ann. Phys.
9
,
499
517
(
1960
).
13.
Reference 3, Eq. (10.19). Since all we're doing is searching for a missing term, we may as well concentrate on V, and set t = 0.
14.
Reference 7, quoted in Eriksen and Grøn, Ref. 2.
15.
Reference 12, quoted in Eriksen and Grøn, Ref. 2.
16.
Lyle (Ref. 2, page 216) thinks it “likely” that the extra terms could in fact be obtained at the level of the Liénard-Wiechert potentials “if we were more careful about the step function,” but he offers no justification for this conjecture.
17.
A.
Zangwill
,
Modern Electrodynamics
(
Cambridge U.P.
,
Cambridge
,
2013
), Sec. 20.3.
18.
C.
LaMont
, “
Relativistic direct interaction electrodynamics: Theory and computation
,” Reed College senior thesis,
2011
.
19.
The sign of the radical is enforced by the condition T>Tr.
20.
Any reader with lingering doubts is invited to check that these fields satisfy all of Maxwell's equations. Note the critical role of the delta functions in Gauss's law and the Ampère-Maxwell law.
21.
The factor (1r·v/rc) accounts for the fact that the rate at which energy leaves a (moving) charge is not the same as the rate at which it (later) crosses a patch of area on the sphere. See Ref. 3, page 485.
22.
The fact that a charged particle in hyperbolic motion radiates has interesting implications for the equivalence principle—in fact, it is this aspect of the problem that has attracted the attention of most of the authors cited here. Incidentally, the particle experiences no radiation reaction force—see
R.
Peierls
,
Surprises in Theoretical Physics
(
Princeton U.P.
,
Princeton, NJ
,
1979
, Chapter 8.)
23.
Reference 3, Eq. (11.73).
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