SOTSP: HOP 203
2012-11-04T15:07:00 to 2012-11-04T17:17:30
Science Goal: Understanding the Driving Mechanisms and Properties of RBEs Using IBIS and Hinode
Program: Fast map, 123"x123", 1-side CCD
Target: disk center
xcen=117 ycen=-402
Instrument: SOTSP
HOP/JOP: 203
Description:
Request to SOT HOP Number 0203 ~1590Mbits/day Combination of SP and NFI observation. The observing procedure is the same for every day during the coordinated observing run. Only the target will change. SP: ~400Mbits/hr, 1200Mbits/day repeat SP IQUV scans (fast map, FOV 110" x 123", 0.32" slit, 20 min cadence) during the coordinated observation. The gaps between SP scans due to the SAA periods are accepted. FG: ~130Mbits/hr, 390Mbits/day NFI Na I D 5896 longitudinal magnetograms (MG 4 V/I), cadence 64 sec, in the observing period. Similar to the SP FOV. 2x2 summing. Other Instruments: The Interferometric BIdimensional Spectrometer (IBIS) at the Dunn Solar Telescope (DST) and adaptive optics (AO) in National Solar Observatory, New Mexico, USA. IBIS will follow a same target region on each day, with Halpha and Ca II 854.2 nm lines (90" x 90" FOV, 5-10 sec cadence, ~27 wavelength points for a full wavelength scan). Parallel G-Band and Ca K imaging channels with FOV of about 120???~120?? and cadence of 1 minute will also be provide by DST. Scientific Objectives: Recent discovery of type II spicules at solar limb (De Pontieu et al., 2007 by using Hinode) and "Rapid Blueshifted Excursions" (RBEs
Langangen et al. 2008 by using IBIS) on solar disc has drawn much attention of solar physicists, mainly because of their rapid heating, high speed upflow only, and potential important role in coronal heating and mass transport for solar wind. However we are still far from fully understanding of their properties and driving mechanisms. More observations are certainly needed for statistical and comprehensive studies of their physical properties in order to understand the underlying driving mechanisms. One of the most promising mechanisms is the magnetic reconnection at small scale. In order to verify this or provide options for alternative mechanisms, we plan to carry out on-disc observations of RBEs using the Interferometric BIdimensional Spectrometer (IBIS) at the Dunn Solar Telescope (DST) in coordination with high resolution and high cadence magnetograms from Hinode SOT/SP and SOT/NFI. We will observe with IBIS using chromospheric H-alpha and Ca II 854.2 nm lines to study the properties (velocity, density, temperature and statistical distribution) of these small-scale ejections. The on-disc magnetic field observations by Hinode allow us to study the geometry and evolution of photospheric magnetic fields associated with these jet-like features so that processes which lead to energy deposition and dissipation, such as flux emergence, convergence, cancellation etc at small scales can be characterized. We also plan concurrent EIS and XRT observations in order to investigate the coronal response, mass and energy outputs of RBEs. We will observe RBEs in different regions (such as active region (AR), plage, inside coronal hole (CH) quiet Sun (QS) and outside CH QS) to study their common and different properties and possible driving mechanisms. We understand and comply that Hinode team now give priority to AR observations that may produce flares. Since we will also observe RBEs in different regions, if there is an AR that may produce flares, we will choose that AR same as Hinode. When there is no flare-productive ARs on the Sun, we then choose to observe QS. We also allow Hinode to change target during the coordinated observation in case a region is producing flares. References: De Pontieu, B. et al. 2007, PASJ, 59, 655-662 Langangen, O. et al. 2008, ApJ, 679, L167 Request to SOT HOP Number 0221 context magnetograms (within part of the FOXSI field of view) Other Instruments: Scientific Objectives: Introduction: The proposed observations are in support of the upcoming launch of NASA?fs FOXSI (Focusing Optics X-ray Solar Imager) sounding rocket. FOXSI will provide hard X-ray imaging observations in the 5 and
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15 keV range at a 50 times improved sensitivity compared to RHESSI. This will allow us to investigate the low-level hard X-ray emission that is predicted in some coronal heating scenarios. The current launch data is confirmed for November 2
the exact launch time is TBC in the next weeks. During the 6-minute FOXSI flight, two different targets will be observed. 1) The first minute will be spent on observing a non-flaring active region (the FOXSI field-of-few is 10x10 arcmin). This will ensure that we will get enough counts to test if the hard X-ray focusing optic works properly. Additionally, it will also allow us to study non-flaring hard X-ray emissions from active regions. 2) During the remaining 5 minutes, FOXSI will point to the quiet Sun and polar region to search for hard X-ray emissions from so-called ?enetwork flares?f (e.g. Krucker et al. 1996). Scientific objectives: Coronal heating is one of the main unsolved problems in Heliophysics. Low-level energy releases at high occurrence rates (so-called nanoflares) are one of the proposed mechanisms to heat the corona (e.g. Hannah et al. 2012). While large flares are known to be an insufficient energy input to heat the solar corona, low-level events are a hot topic discussed in many studies providing different, often controversial results. For active region, Schmelz et al 2009 reported the existence a hot (~8 MK) component, while Warren et al. 2011 does not observe such a signature. While EUV and soft X-ray observations are providing a good estimate of the several-million-degree plasma, hard X-ray observations are uniquely suited to observe hot plasma (typically above ~6 MK). Additionally, non-thermal bremsstrahlung emissions can be efficiently detected. The science objectives for the two different points of FOXSI are as following: For the active region observations, we will be able to search for a non-flaring hot component (a component such as reported in Schmelz et al. would produce a clear signal in the FOXSI data), or at least find a new upper limit. We ask for supporting observations from EIS and XRT to characterize the few-million-degree plasma. For the quiet Sun, FOXSI will be able to search for a non-thermal signature of network flares. The absence of such a signature would clearly show that the quiet Sun network flares do not accelerate electrons in the same way as regular flares. We ask for supporting observations from EIS and XRT to observe the thermal emissions associated with network flares. Furthermore, we ask for SOT observations to provide magnetic context observations. In particular for the quiet Sun it is important to see if the observed hard X-ray events are indeed associated with the strongest magnetic fields
