EMP: The Quiet Killer CSC 1984 SUBJECT AREA C4 EMP: The Quiet Killer The Writing Program Command and Staff College Major M. J. NIELSEN United States Marine Corps April 3, 1984 OUTLINE Thesis statement: EMP is the least understood and most neglected nuclear weapons effect: A discussion of the orgin, effects and defensive strategies is provided. I. Introduction A. NATO battle scenario B. General discussion of contents of paper II. Characteristics or EMP A. The production or the pulse B. The strength or the pulse C. The destruction capability of the pulse III. Some defense tactics A. Hardening B. Passive techniques IV. Conclusion The war that has simmered just below the boiling point for more than forty years is joined. Central Europe, for the third time in this century, is the site of bitter and brutal conflict. The Warsaw Pact forces, after a period of mobilization, initiated a swift multi-axis attack through the Gottinger Corridor, the Fulder Gap and the Hof Corridor. NATO forces initially resisted the Pact onslaught due, primarily, to well prepared defensive positions and a preponderance of tactical air support. But by D+8 it was obvious that the Soviets and their surrogates, while slowed by the tenacity and superior weapons technology of the Allies, were rapidly gaining the upper hand. NATO forces did not delay or disrupt Pact second and third echelon elements; even the amphibious assault con- ducted by U. S. Marines in Norway, while tactically success- ful, failed to achieve the strategic objectives of relieving pressure on the central front. Because of these failures, it is only a matter of days before the enemy forces break NATO's defenses; capture Germany and Denmark and penetrate into Bel- gium and France. In an attempt to stabilize this deteriorating situation, the President of the United States, acting with the unanimous support of the Congress, and in consonance with historic U. S. policy, granted the Commander, NATO forces, authority to em- ploy a limited number of tactical nuclear weapons. II Marine Amphibious Force (MAF) reinforced by a regi- ment from the 1st Marine Division, and a Marine Air Group from the 3rd Marine Aircraft Wing conducted an amphibious assault in Norway and is presently defending the NATO northern flank near Tronheim against an estimated two Soviet motorized rifle divisions (MRD) and a separate Soviet airborne brigade. The MAF has been in continuous heavy contact since the amphibious assault and has suffered moderate personnel and equip- ment casualties. However, the constantly increasing enemy pres- sure is exacting its toll and the MAF commander, concerned with what may be becoming an untenable situation, has requested re- lease of his nuclear weapons. Upon obtaining permission from the appropriate unified commander, the Commanding General, di- rected the Commanding Officer, 10th Marine Regiment, to judi- ciously use nuclear fires to blunt the next general Soviet at- tack. At 0700 the following morning, 4th Battalion, 10th Marines, fired three 2 kiloton (kt) nuclear rounds at the assualting MRD successfully, albeit temporarily, repelling the attack. At 1245 the Soviets mounted another attack preceded by their own tactical nuclear strike consisting of six 5 kt rounds and an unknown quantity of lethal nerve agent. The blast and thermal effects of these strikes heavily damaged Marine facilities and field fortifications and caused numerous casualties, but the physical damage to per- sonnel and equipment was not as severe as had been anticipated. Every leader, from the force Commander down to the CO's of the line companies, had planned for the possibility of a Soviet nuclear strike, and had consequently insured that their Marines were well dispersed and under cover. Battered as II MAF defenses were, the Marines could have held the similarly weakened Soviets had not portions of the MAF's electronic command and control system unexpectedly and catastrophically failed. Vital, apparently undamaged elec- tronic equipment, unexpectedly malfunctioned during this cru- cial period. Unscathed as this equipment appeared, it too was a victim of the Soviet nuclear attack. An Electromagnetic Pulse (EMP), a devastating form of electromagnetic "fallout," generated by the detonation of each of the Soviet nuclear weapons, virtually destroyed II MAF's remaining electronic equipment. The Marines lost the ability to talk over radio, to see with radar, or to exchange data with critically needed external control and coordination agencies. Reduced by direct attack; staggered by blast and heat; sickened by nerve gas; and blinded and deafened by EMP, II MAF forces buckled and collapsed by 2000. Enemy forces seized the initiative and quickly commenced pursuit operations. The foregoing scenario is probably not an accurate de- scription of the sequence of events of the next war in which the Marine Corps may be involved, but it will serve to illu- strate a point. Marines may well be involved in future battles in which nuclear weapons are employed. As professionals, it is essential that we become familiar with the effects of all types or weapons that we may encounter. The nuclear weapon effect that Marines generally ignore or misunderstand is EMP. What is not taken into account is not defended against, and what goes undefended usually becomes an Achilles heel. To plug the chink in the Corps' armor requires education and to that end, this paper will discuss EMP. I will analyze the phenomenon or EMP in two parts. The first will provide a description of the characteristics of the pulse, how it is generated, how it propagates and a brief synopsis of its deleterious effects. The second part will offer some recommendations for measures to improve the Marine Corps' defensive EMP posture. As stated previously, EMP is the acronym for electro- magnetic pulse. The name implies a short-duration emination of some type of harmless electrical energy. Most Marines, if asked, would probably describe EMP in terms of the "blackout" effect which is a naturally occurringupper atmospheric phenome- non that may temporarily disrupt radar signals and radio communications. Unfortunately, this is a false analogy. The blackout effect is basically benign and passive; EMP however, is an intense, active electronically lethal electric and magnetic field created by the ionization of air molecules by gamma radiation produced by a nuclear explosion. This electromagnetic field of sub-millisecond duration may contain sufficient energy to damage electronic or electrical equipment at distances where the traditional nuclear effects of blast, heat and radiation are comparably insignificant.1 Gamma rays,* traveling close to the velocity of light eminate concentrically from the point of fission and impact with surrounding air molecules. These collisions strip electrons from the air molecules' component atoms. The result of these impacts is an electric current that moves through the atmos- phere in the same general direction as the gamma rays. This rapidly expanding sphere of electrons creates a locally intense electric field. The strong, moving electric field thus formed will, in turn, generate other electromagnetic fields at right angles to the initiating field. These induced fields are analo- gous to the electromagnetic fields produced by the rapidly changing electrical current used to generate the transmit sig- nal in a common radio antenna, but of several orders of mag- nitude greater. *Exremely short wavelength electromagnetic eminations (frequency is 10 19 to 10 22 Hz) which behave somewhat like waves. The energy of gamma rays are transported by photons emitted by the raioactive material released by a nuclear detonation. E = hf; where h = Plank's constant and f = fre- quency. For simplicity's sake, I will assume that the electric field radiating radially from the burst is a symmetrical sphere and that the EMP effects are manifested equally at all points equidistant from the point of detonation. To better understand the intense field strength of a "typical", small electromagnetic pulse, the following example extracted from Air Defense Magazine is provided. "A field of 1-to 6- kilometers radius-- radius is yield dependent-- will result from a near-surface burst having a height from 0 to 2 kilometers. In this region, ... the electric field may well exceed 100 kilovolts (kv) per meter, ..."2 As distance from the burst increases, the radiation and blast effects quickly attenuate, but not so for EMP. For example, it is estimated that the electric field strength 10 kilometers from the burst cited in the above example would be approximately 4 kv per meter. Of lesser immediate concern for the tactical commander, but no less serious, is the effect of very high altitude 40 kilometer higher large yield, in excess of one megaton, detonations. Nuclear weapons effects, other than EMP, of bursts at these altitudes are negligible. The EMP generated, however, poses a significant threat to Division and MAF level communications, other electronic systems such as ADPE-FMF, RADARS, tactical computers and power generating systems. A vivid example of the potential devastation of high altitude EMP was inadvertently demonstrated during an atmos- pheric nuclear weapons test in 1962. A device yielding more than one megaton was detonated near Johnson Island in the Pacific nuclear test range. The EMP from this detonation caused power failures, tripped numerous heavy circuit break- ers, and activated hundreds of burglar alarms on Oahu in the Hawaiian Islands nearly 800 miles distant. Considering the comparative primitive nature of the electronic equipment affected by the EMP in this example, it is not difficult to imagine the catastrophic effect a similar pulse would have on the more sophisticated and; therefore, more vulnerable systems in general use today. It has been determined that EMP is generated by the mas- sive ionization that occurs microsecondsafter a nuclear deto- nation. While it is academically stimulating to comprehend the technical details of EMP, it is more important to be conver- sant with what it does. Succinctly, EMP destroys or temporarily degrades electric and electronic systems. Electromagnetic Pulse (EMP), internal electromagnetic pulse (IEMP)* and transient radiation effects on electronics (TREE)** may cause permanent damage ... by burning out or degrading com- ponents by introducing undesirable signals.3 *Some Gamma radiation may directly enter a shelter or enclosure such as a tank, communications van or missile body and actually ionize materials within the enclosure itself, thus generating intense, spurious electronic fields internally in electronic equipment. **Direct damage to semiconductors, FET's MOSFET's and other components caused by direct gamma radiation and neutron bombardment generated incident to a nuclear explosion. The magnitude of the EMP field encountered on the nuclear battlefield may be extremely intense. Vulnera- bility of equipment to this pulse, or series of pulses, is determined by susceptibility of critical internal com- ponents. To compound this problem, individual electronic components or combinations of components have a wide range* of tolerance to EMP induced damage. Unfortunately, the more modern, miniaturized, sophisticated and capable a device, the more likely it is to fail when exposed to a relatively low transient energy level. Microwave diodes, which are used in all tactical short and medium range microwave systems, will fail if pulsed with a wide band signal -- another phrase for EMP -- with an energy threshold of 10-4 to 10-7 Joules.** Integrated circuits used widely in central processors and peripherals of all modern tactical and commercial computers fail when exposed to an EMP energy equivalent of from 10-3 to 10-7 Joules (one one-thousandth to one-tenth of a millionth of a watt.) *on the order of 108 **Joules is a measure of work accomplished where a force of one neutron displaces the point of application one meter in the direction of force. The power necessary to destroy the microwave diode cited above is commuted as follows. Power in watts = 10-7J/sec or .1 of a millionth of a watt. Since an EMP is a short duration pulse, say one thousandth of a second, the power required to destroy the diode junction is increased, but only to one thousandth or 10-4 of a watt. The point is that it takes only minute quantities of unwanted electrical energy to destroy critical electronic components. Tactical VHF, HF and UHF radios will fare somewhat better than computers in a nuclear environment because, at least the types now in general use, contain less sophis- ticated circuitry. Even these older radios, PRC-77 and VRC-12 for example, contain medium and high power transistors and common PN diodes, all of which will fail when subjected to spurious energy pulses of between 10-1 to 10-4 Joules. Not even large electric motors, generators and heavy trans- formers are immune. It is probable that no electrical system, including such items as truck and tank engines, would function if the energy of the EMP exceeded one thousand Joules. How- ever, it is doubtful that this level would be reached in any scenario, except total war, and is, therefore, not relevant in a tactical sense. To this point the discussion has emphasized the mech- anism that generates EMP, the pulse's propagation character- istics and the energy level necessary to destroy various electronic equipment. Of more practice concern, especially when one considers the undeniable fact that U. S. forces are irrevocably committed to the use of an ever increasing quan- tity of sophisticated micro-miniaturized electronic systems, is the problem of implementing a viable defense against the devastating effects of EMP. What pulse resistant equipment, facilities, shielding, if any, is available now? How will active electronic equipment function on the EMP bathed battlefield? What actions can a tactical commander employ today to reduce his vulner- ability? Unfortunately, the answer is, not much. All is not lost, however, and even though the present situation is grim and the prognosis for a rapid "fix" to the EMP dilemma is poor, there are some solutions. EMP defense can be broadly divided into two categories. The first is install more equipment in many different battle- field locations. Dispersing several redundant systems through- out the battle area would allow the commander the luxury of accepting a higher equipment casualty rate. A corollary to this tactic is increased use of passive defense measures by equipment operators. This method would reduce or negate EMP effects by field expedient shielding, physical isolation, and compliance with existing protective methods. The second defense category is for the U. S. to design and field hardened elec- tronic equipment. * "Hardening describes the process of ensuring the equip- ment will work after exposure to the effect of nuclear weapons. Simply stated...equipment is "hard" when it can function after exposure to defined limits of any or all of the four primary effects of a nuclear weapon: blast, heat, radiation and electromagnetic pulse (EMP.)" Incidentally, most new large-scale C3 systems are EMP protected to some degree. Implicit within this second strategy resides the concept of retrofit. Advo- cates of this EMP defense suggest that all military elec- tronic systems now in use should be modified with EMP hardened components. Gaining survivability with command add control equip- ment presently fielded proves more dirricult than achieving redundancy. Two approaches suggest themselves: retrofit and shelters. Simple systems lend themselves to the retrofit approach. Time and cost prohibit changing the design of thousands of frequency modulated radios that carry the bulk of U. S. ground forces command and control traffic.4 To implement the first EMP defense strategy requires a commander to direct two actions. The first is to obtain more electronic equipment and disperse these items throughout the area of operations. This redundancy and dispersion might work if the level of the EMP does not electronically swamp the entire area. This tactic is probably not acceptable to Marines becsuse of the historic paucity of equipment, lack of instal- lation time, and insufficient manpower. Although this method appears unacceptable, it may have some utility depending on the situation, and should not be discarded without due consideration. The other action that a commander can invoke to improve his EMP defense posture is to implement field expedient and operator initiated protective measures. Realistically there is probably little an electronic systems operator can do to EMP harden his equipment. However, every positive action will help and good opera- ator procedure may be the key to the survival of critical C3 equipment. First, all equipment must be operated, maintained and grounded in absolute conformance with appropriate technical manuals. To do otherwiae is to negate whatever design pro- tection that may already exist. Equipment access ports and maintenance doors should be closed. All cables, an- tenna leads and field wire systems should be buried under steel or other metallic shields whenever possible. Connecting cables should be kept as short as possible. Antennas, wires and cables should not be erected near structures, such as fences or power lines, that tend to act as AMP collectors and concentrators. Antennas and cables should be disconnected whenever equipment is not in use. Tactical computers should be kept as far from communications and power generating equipment as possible and should be as electrically isolated* as feasible. *Fiber optic carriers do not transmit information via superimposition on an electromagnetic carrier and are,therefore, immune to EMP. These suggestions may seem primitive but as Lieutenant Colonel SOLLINGER states, "...But a relatively simple addition such as a switch on the antenna lead that opens when subjected to EMP may harden the system sufficiently. Each battlefield command and control system requires an analysis to determine the precise technique."5 As previously indicated, the second category of EMP defense was to use equipment that is design-hardened or retrofit older equipment presently in the active inventory. Research, development and procurement decisions are not within the scope of this papers. However it is the duty of every professional to recognize the threat and to provide informed, timely and accurate input relative to EMP to those who are responsible for the acquisition of new systems or who supervise the Marine Corps' Recovery and Evacuation (R & E) programs. Electromagnetic Pulse, the fourth and often neglected effect of nuclear explosions, is a lethal threat to the commanders ability to control and coordinate his forces on the modern battlefield. As FMFM 11-1 warns, "Although environ- ments producing these effects are of short duration, these effects can be momentary or permanent."6 This immense burst of electromagnetic energy, caused by the rapid ionization of the atmosphere incident to a nuclear explosion, propagates at close to light velocity and permeates electronic equipment. As one EMP analyst points out, "In the event of war, these military dependencies on non-EMP hardened networks could prove an Achilles heel to national degense."7 Present com- munication and electronic systems used by Marines are not scheduled for installation of EMP hardened components or shielding retrofit, nor is state-of-the-art-EMP protected equipment yet available. Therefore, the Corps' tactical systems will remain vulnerable to EMP. The prudent com- mander should be aware of this inherent weakness and should take every action possible to ensure that his unit does not fall victim to the quiet nuclear weapons effect. FOOTNOTES 1Jay Willis, EMP: An Increasingly Important Nuclear Weapons Effect," Air Defense Magazine, Jan-Mar 1983, p. 12. 2Ibid, p. 13 3U. S. Marine Corps, Nuclear, Chemical, and Defensive Biological Operations in the FMF, FMFM 11-4/FM101-31-1, 1981, p. 8-12. 4Jerry Sollinger, Improving U. S. Theater Nuclear 5Ibid, p. 31 6U. S. Marine Corps, Nuclear, Chemical, and Defensive Biological Operations in the FMF, FMFM 11-1, 1982, p. 28. 7Janet Raloff, "EMP: Defensive Strategies," Science News, May 16, 1983, p. 315. BIBLIOGRAPY Broad, William J. "Military Grapples With the Chaos Factor." Science, (Nov 1981), 213 pp,1228-1229. Engle, K. S. R. "EMP: The Invisible Circuit Killer." Science Digest, (Nov 1982), 90 pp. 69+ Fink, Donald G. and Alexander A. McKenzie, eds. Electronics Engineers' Handbook. New York: McGraw Hill, 1975. Glasstone, Samuel and Philip J. Dolan, eds. The Effects of Nuclear Weapons. Washington, D.C.: U.S. Department of Derense, 1977. Raloff, Janet. "A Sleeping Electronic Dragon." Science News, (May 9, 1981), 119 pp. 300-302. Raloff, Janet. "EMP: Defensive Strategies." Science News, (May 16, 1981), 119 pp. 300-302. Sollinger, Jerry M. Improving US Theater Nuclear Doctrine: A Critical Analysis. Washington, D.C.: National Defense University, 1983. U. S. Marine Corps. Nuclear, Chemical, and Defensive Biological Operations in the FMF, FMFM 11-1. Washington, D.C., 1982. U. S. Marine Corps. Staff Officers' Field Manual: Nuclear Weapons Employment Doctrine and Procedure, FMFM 11-4/ FM 101-31-1. Washington, D.C., 1981. Willis, Jay C. "EMP: An Increasingly Important Nuclear Weapons Effect." Air Defense Magazine, (Jan.-Mar. 1982), pp. 12-15.
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