Radiatively driven winds from magnetic, fast-rotating stars

An analytical procedure is developed to solve the magnetohydrodynamic equations for the stellar wind problem in the strong-magnetic field, optically thick limit for hot stars. The slow-mode, Alfven, and fast-mode critical points are modified by the radiation terms in the force equation but in a manner that can be treated relatively easily. Once the velocities at the critical points and the distances to the points are known, the streamline constants are determined in a straight-forward manner. This allows the structure of the wind to be elucidated without recourse to complicated computational schemes

The Constitutionality of Abortion

The purpose of this study is to determine whether abortion is constitutional under the Fourth Amendment. Essentially, the Supreme Court used what is known as the “right to privacy” which they created using the First, Fourth, Fifth and Ninth Amendments finding penumbras of the Bill of Rights, and in the concept of liberty guaranteed by the first section of the Fourteenth Amendment. This study addresses the history of the right to privacy and tries to show that the Supreme Court stretched the meaning of these Amendments beyond what the founders of the Constitution intended. This study analyzed the application of the Fourth Amendment in the cases of Olmstead v. United States, Griswold v. Connecticut and Katz v. United States, in order to show the evolution of the Fourth Amendment. Using dissenting opinions from the cases this study attempts to show that the so called “right to privacy” is unconstitutional and therefore, the Fourth Amendment does not apply to abortion, thereby making the same unconstitutional. The study did discover that although the Supreme Court has declared abortion Constitutional in the case of Roe v. Wade, strong arguments could be made against its Constitutionality. In so doing, this study tries to show that if no general right to privacy exists, then abortion is unconstitutional

Potential Flow Downstream of the Heliospheric Terminal Shock: A Non-Spherical Shock

We have solved for the potential flow downstream of the terminal shock of the solar wind in the limit of small departures from a spherical shock due to a latitudinal ram pressure variation in the supersonic solar wind. The solution connects anisotropic streamlines at the shock to uniform streamlines down the heliotail because we use a non-slip boundary condition on the heliopause at large radii. The rotational velocity about the heliotail in the near-field solution decays as the fourth power of distance from the shock. The polar divergence of the streamlines will have consequences for the previously discussed magnetic pressure ridge that may build-up just inside the heliopause

Probing the Edge of the Solar System: Formation of an Unstable Jet-Sheet

The Voyager spacecraft is now approaching the edge of the solar system. Near the boundary between the solar system and the interstellar medium we find that an unstable ``jet-sheet'' forms. The jet-sheet oscillates up and down due to a velocity shear instability. This result is due to a novel application of a state-of-art 3D Magnetohydrodynamic (MHD) code with a highly refined grid. We assume as a first approximation that the solar magnetic and rotation axes are aligned. The effect of a tilt of the magnetic axis with respect to the rotation axis remains to be seen. We include in the model self-consistently magnetic field effects in the interaction between the solar and interstellar winds. Previous studies of this interaction had poorer spatial resolution and did not include the solar magnetic field. This instability can affect the entry of energetic particles into the solar system and the intermixing of solar and interstellar material. The same effect found here is predicted for the interaction of rotating magnetized stars possessing supersonic winds and moving with respect to the interstellar medium, such as O stars.Comment: 9 pages, 4 figures, accepted for publication in ApJ

Potential flow downstream of the heliospheric terminal shock: A non-spherical shock

We have solved for the potential flow downstream of the terminal shock of the solar wind in the limit of small departures from a spherical shock due to a latitudinal ram pressure variation in the supersonic solar wind. The solution connects anisotropic streamlines at the shock to uniform streamlines down the heliotail because we use a non-slip boundary condition on the heliopause at large radii. The rotational velocity about the heliotail in the near-field solution decays as the fourth power of distance from the shock. The polar divergence of the streamlines will have consequences for the previously discussed magnetic pressure ridge that may build-up just inside the heliopause

3D Emission & Physical Chemistry Simulations of the Io Plasma Torus

The Galilean moon Io emits volcanic gases into space at a rate of about a ton per second. The gases become ionized and trapped in Jupiter&rsquo;s strong magnetic field, forming a torus of plasma that emits 2 terawatts of UV emissions. After reanalyzing UV emissions observed by Voyager, Galileo, &amp; Cassini, this work found that the Voyager plasma conditions were consistent with a physical chemistry model with a neutral source of dissociated sulfur dioxide from Io. The Voyager analysis of Shemansky (1988) [121] found an O/S ratio of the neutral source of 4 required to match UV observations whereas we find it to be 2 consistent with dissociation of SO2. There are plenty of ways I could see it being less than 2 when also including sources from SO, S2, and other sulfur compounds but it is much harder to explain it being larger than 2. By using a double Maxwellian distribution where both the core thermal electrons as well as supra-thermal &ldquo;hot&rdquo; electron population are assumed to be Maxwellians I have modeled the emission in the UV using the CHIANTI atomic database. This double Maxwellian model of UV emission spectra when compared with a spectrum from CASSIN UVIS at 6 RJ does not well constrain the fraction of hot electrons. Additional physics from energy constraints from physical chemistry modeling allows me to determine that for nominal warm torus plasma parameters the fraction of hot electrons is about 0.25% at 6 RJ. This research determined the mass and energy budget and dominant chemical pathways in the Io plasma torus. This result is particularly important due to the abundance of recent spectral analyses of UV data from JAXA's Hisaki satellite. Spectral analysis of the Hisaki observations has found fractions of hot electrons on the order of a few percent (Yoshioka et al. (2014); Tsuchiya et al. (2015))&nbsp; [163] [150] inconsistent with our model and previous results. ESA's JUICE mission and NASA's Europa Clipper are sending UVS instruments to the Jupiter system that will view the Io plasma torus. In anticipation of these missions, I have built a 3D Io plasma torus emission model in order to simulate what we would expect to see from both UVS instruments looking at the Io plasma torus. In addition, our model allows for observation planning to predict if particular torus stare scenarios will produce sufficient signal to determine plasma conditions. The Colorado Io Torus Emission Package 2 (CITEP 2) calculates the line of sight given the position and pointing of the spacecraft and produces a synthetic spectrum given plasma densities and temperatures along the line of sight using the CHIANTI atomic database version 9 to compute volume emission rates. I have adapted and built upon a 3D model of the physical chemistry (Copper et al. (2016)) [33] while varying the neutral source rate and diffusion coefficient in order to model the warm torus, ribbon, and cold torus self-consistently. I have corroborated Copper's results and adapted the model for my own purposes. I have moved the model in from the warm torus to simulate the cold torus, gap region, ribbon, and warm torus. I am able to produce the ribbon and a peak in flux-tube content at L=5.7 by applying a discontinuity in the diffusion coefficient in that region consistent with a change in flux-tube interchange processes. By applying the &ldquo;notched" DLL profile that Taylor (1996) [142] used for a few model runs I was able to produce a cold torus peak and gap region by fixing the neutral density profiles to the Koga et al. (2018b) [79] scaled up by a factor of 1.5 but with a fast power law fall of +20 and cutting it off inside 5.65 RJ. I found that if I didn't have the neutral densities fall off much steeper than the Koga et al. (2018b) [79] implied power law of +12 inside 5.7 than my electron and ion temperatures would stay far too high due to pickup energy. This implies that inside the peak in neutral density at 5.7 RJ Koga et al. (2018b) [79] was overestimating densities due to line of sight projection effects. I investigate the tipping point of inflow versus outflow of mass and energy and quantify the transport timescales given the diffusion coefficient profile and flux tube content radial profiles. I found radial transport timescales ranging between tens of days to hundreds of days in the warm torus depending on the method used and many hundreds of days to a thousand days in cold torus. I found a separable transient solution to the radial Fokker-Planck equation I have never seen applied to Jupiter for flux-tube interchange motion. I found an e-folding timescale for the transient separable solution exactly the same as what is used as a radial transport timescale in the literature and found similar values for this e-folding timescale to match the torus profiles as is found using the integrated transport timescale formulation. I performed a numerical experiment to determine the time for a perturbation to move through the warm torus. By taking our nominal steady-state output in the warm torus and perturbing the solution at L=6 we find shorter timescales for the perturbation to reach L=10 of about 30 days as opposed to around 100 days for the integrated transport timescale. The output of our 3D physical chemistry model produces a 3D model of densities and temperatures which can be used in conjunction with CITEP 2 to simulate corresponding emission profiles for a given viewing geometry. </ul