Air Support in the Breskens Pocket: The Case of the First Canadian Army and the 84 Group Royal Air Force

Operation “Switchback” was conceived to capture the Breskens pcoket and liberate the south bank of the Scheldt Estuary leading to Antwerp. As the Allies moved out of Normandy in the late summer of 1944, their primary supply line remained over the invasion beaches. The logistical situation became critical as the distance fromthe beachhead lengthened. The British scored a major coup in early September when they captured the port of Antwerp. Not only was this the largest port in Europe, it had been taken with its port facilities intact. Unfortunately, there remained one problem; Antwerp lay some 50 miles from the Sea. The only approach to the port lay along the Scheldt Estuary. The Germans controlled both banks of this channel and were determined to hold out to the last. Until the land on either side could be liberated, the port of Antwerp was useless to the Allies

“The Development of an Unbeatable Combination”: US Close Air Support in Normandy

In the climactic scene of the highly-acclaimed Saving Private Ryan, the beleaguered Ranger and Airborne forces of Captain John Miller (Tom Hanks) are about to be overrun. Against overwhelming odds they have fought to save a crucial stone bridge over the Merderet River. It is a losing battle. With defeat imminent, the Americans retreats across the bridge and prepare to blow it. However, before that can happen, Captain Miller is shot and is unable to detonate the explosives. As a German tank rumbles across the bridge it appears all is lost. Then, in typical Hollywood tradition, the calvary arrives--two P-51 Mustangs. With uncanny timeliness and pinpoint accuracy they knock out the German tank on their first pass without destroying either the bridge or the American infantry who are mere yards away. Though this may be a fitting end to a very good movie, it is not representative of the capabilities of tactical air power, especially early in the Normandy campaign. Leaving aside the question of accuracy, the system of air support in place at the outset of the invasion was much too cumbersome to allow an intervention of this nature. The Americans went into Normandy with a system of Close Air Support (CAS) that was largely derived from the British experience in North Africa. It was based on the belief that centralized contrl of air assets was the most effective method of employment. However, following D-Day, the system in place was far too unwieldy to provide effective support. Over the next three months, most of the existing doctrine was effectively discarded. An air support organization emerged that was the complete antithesis to that with which the Americans had started. The system which evolved proved to be highly effective, flexible and able to adapt quickly to a variety of situations

Statistical repulsion/attraction of electrons in graphene in a magnetic field

The aim of this work is to describe the thermodynamic properties of an electron gas in graphene placed in a constant magnetic field. The electron gas is constituted by $N$ Bloch electrons in the long wavelength approximation. The partition function is analyzed in terms of a perturbation expansion of the dimensionless constant $(\sqrt{eB}L)^{-1}$. The statistical repulsion/attraction potential for electrons in graphene is obtained in the respective case in which antisymmetric/symmetric states in the coordinates are chosen. Thermodynamic functions are computed for different orders in the perturbation expansion and the different contributions are compared for symmetric and antisymmetric states, showing remarkable differences between them due to the spin exchange correlation. A detailed analysis of the statistical potential is done, showing that, although electrons satisfy Fermi statistics, attractive potential at some interparticle distances can be found.Comment: Physica B, 201

Valley properties of doped graphene in a magnetic field

The aim of this work is to describe the electronic properties of graphene in a constant magnetic field in the long wavelength approximation with random binary disorder, by solving the Soven equation self-consistently. Density of state contributions for different valleys in each sublattice sites are obtained for different values of magnetic field strength showing remarkable differences between K and K' valleys. A band gap is obtained by an asymmetric on-site impurity concentration and the graphene electrons acquire an anomalous magnetic moment, which is opposite in different valleys, which depend highly in the interplay between the impurity band, the band edges and the broadening of the Landau levels. In turn, magnetization as a function of B for different on-site random impurities is computed showing that by decreasing the on-site impurity energy values, maximum magnetization is shifted towards higher values of B which can be used to create and manipulate polarized valley currents. Finally, conductivity and local vertex function are obtained as a function of energy showing that scattering contributions from A and B sublattices differ significantly. Effective medium local two-irreducible vertex is computed showing that scattering from sublattices A and B do not contribute equally, which can be related to weak anti-localization. From these results, it could be possible to explore how the valley pseudospin can be used to create polarized currents by populating asymmetrically the sublattice sites, where the population can be tuned with the applied magnetic field strength