ULF Doppler oscillation of L = 2.5 flux tubes

first_imgPlasmaspheric ducts may execute Doppler oscillations driven by propagating ultra-low frequency (ULF) waves. We examined about 100 such events recorded over 1 year under magnetically quiet conditions at L = 2.5 using artificially generated whistler-mode VLF signals and ground magnetometers. Joint peaks in the VLF Doppler and magnetometer spectra occurred at the frequency expected for ULF waves generated by the ion-cyclotron instability in the upstream solar wind. The VLF Doppler shifts are most likely due to radial motion of flux tubes of a few kilometers, driven by the east-west electric field of propagating ULF waves. When the frequencies match, the incoming wave energy also couples to standing poloidal and azimuthal field line oscillations, producing field line resonance signatures in both the D and H components on ground-based magnetometers. The phases of the VLF and ULF oscillations are consistent with ionospheric rotation of the downgoing ULF wave field. Since the scale size of VLF flux tubes is significantly smaller than for ULF flux tubes, VLF Doppler observations can provide more precise spatial information on ULF wave fields in the plasmasphere. Furthermore, it should be possible to use ULF oscillations to monitor the formation of quarter wavelength mode standing field line oscillations when the conjugate ionospheres have different conductivities.last_img read more

Industrial Gold Coast house takes on glamorous renovation

first_img50 The Promenade, Isle of Capri.INSPIRED by old cotton mills in England, Homeowners Paul and Lynn Maddison have proven that industrial design can be just as glamorous. The couple said the idea for the bold and beautiful design came from converting old cotton mills into trendy apartments in the late 80s. More from news02:37Purchasers snap up every residence in the $40 million Siarn Palm Beach North4 hours ago02:37International architect Desmond Brooks selling luxury beach villa1 day ago50 The Promenade, Isle Of Capri.“We are originally from Manchester and after we did the cotton mill project we have been obsessed with playing with old and new concepts since,” Mrs Maddison said.The English expats who run PM Concepts said the renovation at 50 The Promenade took them eight months. 50 The Promenade, Isle of Capri.Mrs Mattison said she wanted the house to have a sense of age combined with New York loft style but said it was difficult to buy a property with heritage on the Gold Coast. “We found reclaimed bricks from Melbourne that still had original branding on them,” she said.last_img read more